Which of the Following Must Be True About the Very

Which of the following must be true about the very first stars?

A) They couldn't form until billions of years after the Big Bang.
B) They were made of dark matter.
C) They all had low (less than 1 M_SUN) masses.
D) They formed in large clusters of millions of stars, which became galaxies.
E) The material from which they formed contained no elements more massive than lithium.