The word trivial can be learnt by splitting it up as trivial=three+vs+all , so the choice of 3 persons is given little importance when compared to choice of all.
Meanings of Trivial:
1. of very little importance or value; insignificant.
2. commonplace; ordinary.
Sentence Examples for Trivial:
1. The proposal by Anand is trivial to implement, but will not be suited for fine control.
2. Please do not expect them to deal with relatively trivial matters which could or should be sorted out by your son or daughter.
3. A side effect doctors may consider trivial might be totally unacceptable to a patient.