Which sentence is correctly punctuated with a colon?
a. in 2010: shaun white placed first in key competitions usaa grand prix finals, dew tour skateboarding, and winter olympic half-pipe.
b. in 2010, shaun white placed first in key competitions: usaa grand prix finals, dew tour skateboarding, and winter olympic half-pipe.
c. in 2010, shaun white placed: first in key competitions usaa grand prix finals, dew tour skateboarding, and winter olympic half-pipe.
d. in 2010, shaun white placed first in: key competitions usaa grand prix finals, dew tour skateboarding, and winter olympic half-pipe.