When Bumi enters, choose up to X, where X is the number of Lesson cards in your graveyard —
• Put three +1/+1 counters on Bumi.
• Target player scries 3.
• Earthbend 3. (Target land you control becomes a 0/0 creature with haste that's still a land. Put three +1/+1 counters on it. When it dies or is exiled, return it to the battlefield tapped.)
You can't choose the same mode of Bumi, King of Three Trials's triggered ability more than once. As there are only three modes, even if X is greater than three, you won't get additional effects after choosing each mode once.