Which statements correctly describe the grana and stroma? Select two that apply.

A. Inside the outer membranes is a gel-like fluid known as the stroma.
B. Inside the outer membranes is a gel-like fluid known as the grana.
C. Stacks of thylakoid membranes are collectively called the stroma.
D. Stacks of thylakoid membranes are collectively called grana.