Answer:
a) the advantages a candidate who is running for re-election has over the candidate trying to unseat him or her
Step-by-step explanation:
Incumbency effect can be defined as the advantages a candidate who is running for re-election has over the candidate trying to unseat him or her in a democratic election process.
Basically, it refers to the tendency (phenomenon) for public officials such as senators or house of representative members who are already holding power (office) to get re-elected over an opposition. This ultimately implies that, a candidate contesting with an incumbent candidate is automatically placed at a disadvantage to emerge as the winner election due to the power of incumbency (incumbency effect).
Additionally, the incumbency effect is peculiar to democratic elections and most favorable or stronger for the house of representative members.