Statement #1 ) : the unit digit of (n+4 ) ^ 2 is 4 : we know that the unit digit of 8^2 is 4 and also the unit digit of 12^2 . so n+4 could be 8 and 12

so n+4 = 8 and here n =4 OR n+4= 12 and Here n=8 so Two different integer and two different result . so Data # 1 Is insufficient.

Statement#2) : the unit digit of (n+3)^2 is 1 : we know that 9^2 has 1 in its unit digit and also 11^2 has 1 unit digit so n+3 = 9 OR 11 and n could be 6 OR 8 this Data

has 2 possible value and is ruled out too....

Combined info : we get 8 from 2 info in common so sufficient ... Answer is C