because when a trigonometric ratio is impressed by using π/2 the ratio should be changed its opposite like sin value turns into a cos value, tan value turns into cot and vise versa. Then as 135° is in the second sector that means π/2<135°<π. So it should be -tan(45°)
As tan-45°= -tan 45° i think the answer is second one aka cot(135°)
