Comprehension \( \quad \) Consider two points \( A=(1,2) \) and \( B=(3,-1) \). Let \( M \) be a...

Comprehension \( \quad \) Consider two points \( A=(1,2) \) and \( B=(3,-1) \). Let \( M \) be a point on the straight line \( L: x+y=0 \).
If \( M \) be a point on the line \( L=0 \) such that \( A M+B M \) is minimum, then the reflection of \( M \) in the line \( x=y \) is
(a) \( (1,-1) \)
(b) \( (-1,1) \)
(c) \( (2,-2) \)
(d) \( (-2,2) \)