Which conditions on earth’s surface will allow
for the greatest amount of water to seep into the
ground?
(1) gentle slope and permeable
(2) gentle slope and impermeable
(3) steep slope and permeable
(4) steep slope and impermeable

A gentle slope means that the water will run down slower, and if the slope is very very gentle  - basically if the ground is flat, water might stay and form a lake.

Af the ground is impermeable, this means that water cannot go through it - or only very slowly- so the more permeable it is, the more water will go through it.

so the best answer is - steep slope and permeable.