Gimme ur best pickup line

Could someone . i have tried to solve myself but my calculation is off

The star betelgeuse is about 600 light-years away. if it explodes tonight, a. we'll know because debris from the explosion will rain down on us from space. b. we'll know it immediately because it will be brighter than the full moon in the sky. c. we won't know about it until 600 years from now. d. none of the above.

This is for my 8th grade science class, i really don’t understand. can someone me? , lol.