Which air mass would produce warm, humid weather in the summer?
a. maritime polar
b. continental tropical
c. maritime tropical
d. continental polar?

The correct option is C.
The maritime tropical air mass typically produce warm, humid weather in the summer. The air mass originate from over the warm water of the tropics and Gulf of Mexico, where heat and moisture are normally transfer to the air above from the water below. The tropical air masses, which then move northward transport the moist warm air into the USA.

What are the following resources?

It is the second answer