All ar, er and ir preterite endings.

There are only two sets of endings for regular preterite verbs, one for -ar verbs and one for both -er and -ir verbs. To conjugate a regular verb in the preterite tense, simply remove the infinitive ending (-ar, -er, or -ir) and add the preterite ending that matches the subject. Check out the table of regular preterite endings below.

AR:

yo-é

tú-aste

él/ella/usted-ó

nosotros(as)-amos

ellos/ellas/ustedes-aron

ER/IR:

yo-í

tú-iste

él/ella/usted-ió

nosotros(as)-imos

ellos/ellas/ustedes-ieron

answer: the answer is b. se quejan because it's in the plural form.