We are given the curves y=∫−∞xf(t)dt through the point (0,21) and y=f(x), where f(x)>0 and f(x) is differentiable, ∀x∈R through (0,1). If tangents drawn to both the curves at the points with equal abscissae intersect at the same point on the X-axis, then
The function f(x) is
a. increasing for all x
b. non-monotonic
c. decreasing for all x
d. None of these