I am very confused (I didn’t mean to press B)

Answer:
The anwer is A
Step-by-step explanation:
If it is a right angle triangle we use paythagoras theorem
a ×a + b× b= c × c
1. 15× 15( square of 15) + b× b(square of b) = 17 ×17 (square of 17)
;2. 225 + b×b(square of b ) = 289
3. b×b(square of b) = 289-225
4. b × b( square of b )= 64
[tex] \sqrt{b \times b} = \sqrt{64} [/tex]
b = 8
I hope it is helpful