Which is the best explanation of how american and french forces used the physical geography of the area to their advantage in the siege of yorktown? a) the american and french troops made a successful charge on the british, who entrenched on the high ground of the battlefield. b) they pinned the british against the york river and waited for it to ice over in the winter, preventing the british from being resupplied. c) the americans hired indian scouts for their knowledge of the terrain and the fact that they knew shortcuts for attacking the british positions. d) the american troops surrounded the british lines and began to shell them, while the french navy blocked any chance for their escape by blockading the york river.