The correct option is C 8
All the numbers in a Pythagorean triplets are natural numbers and given, the largest number of a Pythagorean triplet is 17.
If one of the other numbers is
a) 13, then the third number will be
√172−132=√120, not a perfect square.
b) 12, then the third number will be
√172−122=√145, not a perfect square.
c) 8, then the third number will be
√172−82=√225=15, a perfect square.
d) 9, then the third number will be
√172−92=√208, not a perfect square.
Hence, the smallest number in the Pythagorean triplet with the largest number in it as 17, is 8.