5. Los beisbolistas están jugando en el campeonato.
Explanation:
identifying the narrator, the gender and the number in each sentence is the first step when completing them, we must bear in mind that the progressive form of the verbs indicate actions that are being carried out in real time, therefore at the moment of conjugating the Verbs we must do according to the time given in each sentence and thus have agreement with what you want to express.
ER verbs ending conjugations are verbs with infinitives ending in -er form a second group of regular verbs in Spanish, often called second conjugation verbs.