Please help me with this question, no links please, thank you!!!

A school has all of the students in grade 7 take a spelling test. Several samples are taken from the results. Which of the following samples is NOT likely to produce a representative sample of the population?

Group of answer choices

20 students who have science first period.

3 students who were in the final round of the spelling bee.

15 students whose name begins with N.

40 students who say math is their least favorite subject.