This is the 4482nd most frequent Korean word.
후보들의
"Of the candidates."
In this sentence, '후보들의' functions as a possessive form indicating 'of the candidates', attributing the opinions ('의견') to them.
후보들의 의견을 경청해야 합니다.
We should listen to the candidates' opinions.
Here, '후보들의' shows possession, referring to the preparations ('준비') belonging to the candidates.
후보들의 준비가 더욱 철저해졌습니다.
The candidates' preparations have become more thorough.
In this example, '후보들의' modifies '연설', elucidating that the speeches are those of the candidates.