(a) It is recessive.
If it was dominant, it would have appeared in more than 1 child.
None of the children would have sickle cell anaemia/0% children would have sickle cell anaemia.
Ram's genetic composition: Ss
Asha's genetic composition: Ss
Four possible genetic compositions in children: SS, Ss, Ss, ss.
So, the composition of the other three children would either be Ss or ss.