Therefore I ended with Option B, seeing that it has a good ratio mixture of special and normal kids, and teachers are prepared to accept special kids.
The teaching style will have more attention to special kids in one to one short sessions.

It's too early to tell if it is the right choice, only time will tell, and hope I made a right decision.

When I consulted my Occupational Therapist on the choice of school, one of the key points he highlighted to me is the teacher's ability, how the teachers can manage the flow.

If teachers are good, 12 students to 2 teachers look fine.

If teachers are not good in managing the flow in the class, a single teacher would struggle against 3 autistic kids.

Hard decisions when an Autistic is high functioning, but remember, he is still Autistic and they are unique no matter their level. My suggestion is the school idea for special needs children. They usually understand the many levels of his learning abilities as well as his emotional and mental abilities and most times adjust the program to the child not the child to the program.

About B) option, I paid the center a visit, it's a private school that accepts autistic kids.
Principal is accommodating.
However, I need to send my child for a trial for one week in the pre-school class, as they already have a few autistic (already reached their quota for autistic), they want to ensure he can be managed well by them, in order to be fair to other kids.
Principal not rejecting me upfront because she said it is not fair to reject my son without seeing him.
Fingers crossed hopefully it works out.

During my visit, which was during their break time, looking at a few different grades and pre-school as well, so far it looks alright to me.
Those Grade 3 and so on, has a couple of autistic, but they are well behaved, and can talk to me when principal asked them to greet me.

Those pre-school (which my son supposed to be in), there's one autistic who's having speech delay, looks pretty calm.
And the two teachers, first impression is alright.
But it was during break and couldn't see how they manage the lessons.

But to continue further on Option C in above post ....maybe it could be possible. ..

I do not have teaching experience, and within 1 year period (past one year), my wife and myself had managed to teach my difficult son (who hates students and do plenty of manipulative negative behaviors to escape from doing studies, though we thankfully are patient enough most of the time,).
In past one year, we had managed to teach my son, who knows practically nothing academic wise before that ,....and today he knows.
All our teachings are done at night after we finish work, (not every night though).

- A till Z, capital and small letter
- basic phonic sounds AT, AP, ICK, INK, ALL and how they combine with words, this is still something new, and a hit and miss at the moment, sometimes he gets it right..
combination of T + all, means say tall and he understands the meaning...
The feeling is we are on the right track and workable.

- And he knows how to count 1 to 10,....and if we give him pictures , he can count and write correctly example...5 or 7 or 9 objects.

We had moved on to counting 20 objects and 30 objects, but he is still abit confused, but our feeling is he could eventually master it.

We still haven't move on to add / subtraction yet.