Which of the Following Best Describes the Spread of Islam

Which of the following best describes the spread of Islam after Muhammad's death?

A) The religion spread as Muhammad's successors militarily expanded the new Muslim state into Byzantine and Sasanid territory and throughout all of Southwest Asia.
B) The religion spread as preachers and merchants carried the new Muslim faith throughout Southwest Asia.
C) The spread of Islam was extremely slow after Muhammad's death as his successors struggled for power.
D) Islam was largely spread through the help of socially elite women who had converted during Muhammad's lifetime.