Answer:
True
Step-by-step explanation:
This can be explained in accordance with the General Relativity theory of Einstein's which says that the time dilation depends directly on the intensity of gravitational field (for an observer outside the field).
So, as the intensity of the field increases so does the time dilation.
The black hole has highly intensified gravitational field and as such the time dilation near the boundary of the black hole also increases immensely and stops at the event horizon.
Thus the gravity of a black hole is sufficient enough to slow down a clock as one gets nearer to it.