help. (1) Coyotes usually work together _______ they hunt large animals like deer. (2) They take turns chasing the animal until it gets too tired, _______ they drive the animal toward another coyote that is hidden. (3) With the help of its pack, the average coyote can bring down a 550-pound animal _______ it weighs less than 50 pounds. (4) A hunt can last up to 21 hours _______ coyotes do not give up easily.

Which word best links the ideas in sentence 4?
A.
although
B.
since
C.
yet
D.
unless