lets start by listing the factors of 12
1 x 12 = 12
2 x 6 = 12
3 x 4 = 12
since it's a 2-digit integer the 1-12 combination is out. (twelve cannot be 'a digit')
next list the numbers that can be formed with the remaining factors
26
34
43
62
now lets look at 1)
sum of perfect squares in 1 way
26
--> 1 & 5 => 1 & 25 = 26
2 results in 4 and 22 which is not a perfect square
3 results in 9 and 17 which is prime
4 results in 16 and 10, which is not a perfect square
5 puts us back in the first situations
SO: 26 matches, however, we are looking for a single number so none of the others should be possible to be represented as a sum of perfect squares, or should be possible to be represented as different summs of perfect squares
-->looking at 34
1 gives 1 and 33 --> not a perf square
2 gives 4 and 30 --> not a perf square
3 gives 9 and 24 --> not a perf square
4 gives 16 and 18 --> not a perf square
5 gives 25 and 9 --> 2 perfect squares
6 gives 36 which is larger than 34
we found 2 possible n values
1 is not sufficient
2)n is smaller than 40
straight out we can have 26 and 34 --> multiple values = not sufficient
1+2) since the 2 values smaller than 40 are also the values that we found complied to 1), this means we still have 2 possible values
Not sufficient --> E
kudos if it helped