At What Times During the Big Bang Were All Four

Multiple Choice

At what times during the Big Bang were all four fundamental forces unified?

A) until 10^-24 s, after the start of the Big Bang, when the inflationary era ended
B) during the first 500,000 years from the start of the Big Bang, when the universe was dominated by radiation
C) until 10^-6 s after the start of the Big Bang, when the era of quark confinement ended
D) during the Planck era, up to 10^-43 s, after the start of the Big Bang