The person wanted to use her ear to detect the buffalo herd, where did she put it?\nOptions:\n- on the buffalo\n- person's head\n- side of head\n- ground\n- serial killer's bedroom
Step-by-step reasoning process below:

User
When buffalo herd arriving from far you can hear noise putting ears on ground. Runnning buffalo herd makes large impact on ground. The answer: ground.
Assistant