How Does a Period of Extremely Fast Inflation Very Early

Multiple Choice

How does a period of extremely fast inflation very early in the history of the universe explain the observation that the geometry of the universe looks flat (not curved) to us?

A) during inflation a lot of the mass drained out of the universe, leaving its gravity much weaker
B) inflation increased the size of the universe so much that the resulting universe looks flat from any point of view
C) inflation led to the production of so much dark matter that the universe got pulled into the shape of a black hole
D) inflation caused the temperature of different parts of the universe that can't see each other still be the same
E) The universe is actually highly curved and not flat
Section 29.7: The Anthropic Principle