The correct answer to this question is this one: "C. 17." Hope this helps answer you question.
-4, 5, 4
-3, 7, 6
----------
7 12 10
49+144+100= 293
After that,
sqrt(293) is greater then 10, 11, 12, 13, 15, 17 is looking plausible yes
Or we can possibly say that
29^2 = 4xx
15^2 = 225
sqrt(293) = 17.11