The correct options are
A The caribou are driven by lines of people into lakes or narrow streams, where they are speared, shot with bows and arrows or even harpooned.
C Eskimos set up piles of stones in long lines to trap the caribou.
Caribou hunting is essential for nearly all Eskimo groups. These animals are hunted in the inland during summer and early autumn. In some places, they are driven by lines of people into lakes or narrow streams, where they are speared, shot with bows and arrows, or even harpooned. Sometimes, Eskimos set up piles of stones in long lines. To the caribou, the stones look like people in the distance. The caribou would turn away from the lines of stones and thus, be caught.