Under the spoils system in federal and state governments,
a. elected officials appointed supporters to key positions.
b. deserving people received government positions.
c. government officials remained in key positions.
d. democrats were appointed to key positions.

The answer is letter a. elected officials appointed supporters to key positions. Since they were helped by these people, they offer positions in government in return for their support.  This also strengthens their hold on government since these people will promote their platform to the masses.

elected officials appointed supporters and key positions

the exclusive possession or control of the supply or trade in a commodity or service.