Find the missing number?

Answer: Option A

For each star, add the outer numbers together and divide by 3 for the left hand, 4 for the centre, and 5 for the right hand, putting the result in the centre.

For Left Circle:
7 = ( 6 + 4 + 2 + 6 + 3)/3

Right Circle:
5 = (5 + 3 +2 + 9 +1)/4

So, for Bottom Circle,
7 = (11 + 6 +5 + 7 + X)/5
35 = 29 + x
x = 6
Missing Number = 6.