If point P(3,10) is reflected across the line y=1, what are the coordinates of it's reflection image ?
A(3 , -10)
B(-1 , 10)
C(3 , -8)
D(10 , 3)
A(3 , -10)
B(-1 , 10)
C(3 , -8)
D(10 , 3)