What is the possessive pronoun in this sentence: the idea for a group skate was theirs

Dentify the reasons that support the claim. check all that apply. claim: students should be required to take at least one online class. learning entirely remotely is one option that many schools offer. online classes provide more flexibility in students’ schedules. everyone enjoys using a computer, so online learning is more fun than traditional learning. one online class should be a mandated part of any school’s curriculum. students learn valuable skills they can apply in online college courses.