Which sentence has a misplaced adjective clause?

a.
we placed our chairs by the pool's edge, which were bulky and difficult to carry.

b.
the lifeguard, who is a college student, paid close attention to the storm clouds.

c.
the water slide that greets you at the park's entrance is huge!

d.
the children especially enjoyed the water slide, which deposited them into the deep end of the pool.