Which statement most accurately describes presidential elections?
a. they are often close contests between candidates from the democratic and republican parties.
b. they are often landslides in favor of candidates from third parties.
c. they are generally won by candidates from the republican party.
d. the democratic candidate usually wins the presidency, and the republican candidate becomes vice president.

The first alternative is correct.

Presidential elections are held between a Republican and a Democratic Party candidate.

 The dispute concentrates on two distinct projects and the democratic game allows either of them to win, depending on the will of the voter. In fact, hardly a party stays in power for long. Normally, there is alternation between Democrats and Republicans.

For example, Obama was from the Democratic Party. Now it's Trump from the Republican Party.

its d i know cause i've been googling it