Which of the following is a complex sentence? a
Although Jason and Harriet hurried down to the shore, they arrived too late to see the sailors.

b
Harriet told Jason to hurry up. The sailors were going to leave the harbor and travel far away.

c
Jason and Harriet hurried down to the shore, and the sailors floated off into the distance.

d
Jason and Harriet hurried down to the shore and watched the sailboat into the distance.