write the number k as abc where a,b,c are the digits.

for statement 1 : when you add 9 to abc, you first add 9 to c. Since c is non zero, no matter what it is, it will make the addition end up with a 2 digits number. That means, you will have to carry 1 to b or mathematically, b's new value will be b+1. (So, the original b was 2; 3-1 = 2.)

for example say c = 1 , then c + 9 = 10 so abc + 9 becomes a(b+1)0

for statement 2 : since we do not know if adding 4 will result in a carry over to b, this statement is useless by itself.

So the answer is A .

Let K = ABC, where A is the 100th digit, B is the 10s digit, and C is the units digit. From the question we know that C <> 0

Statement 1 - ABC + 9 = 3, If C <> 0 then C + 9 will be > 10, and will carry a power of one to B therefore we know what b = 2 - Sufficient
Statement 2 - ABC + 4 = 2, If C = 8, then B = 1, If C = 3, then B = 2 - Insufficient