Question

A = a+b+c / 3

Answer 1

The equation given in the question is 

A = a+b+c / 3
3A = a + b + c
3A - a - c = b

From the above deduction, it can be easily concluded that the correct option among all the options that are given in the question is the first option or option "A". I hope that this is the answer that has actually come to your desired help.