If then lines (y-b) = m₁(x+a) and (y-b) = m₂(x+a) are the tangets to the parabola y²=4ax, then:

A) m₁+m₂= 0

B) m₁m₂= 1

C) m₁m₂= -1

D) m₁+m₂= 1