Explanation:

N = 55⁵ + 17⁵ – 72⁵
N = (54 + 1)⁵ + (18 - 1)⁵ – 72⁵
The above is divisible by 3

N = (51 + 4)⁵ + 17⁵ – (68 + 4)⁵
The above is divisible by 17
N = 55⁵ + (11 + 6)⁵ – (66 + 6)⁵
The above is divisible by 11
N cannot be expressed in favourable of 7 and 13 and hence is not divisible by 7 and 13
From the above the best answer choice is (B) – N is divisible by both 3 and 17

The question is "which of the following is true?"

Hence the answer is N is divisible by both 3 and 17.

Choice B is the correct answer.