What volcanic events formed Crater Lake, OR? When did they take place?

Question

Question: What volcanic events formed Crater Lake, OR? When did they take place?

Options:

1.  A powerful explosion blew away the top of a stratovolcano; 10 million years ago.
2.  The crater of a large, extinct cinder cone filled with water; 5 million years ago.
3.  Landslides and volcanic mudflows dammed the Mazama River; 500 years ago.
4.  Caldera collapse followed major ash and pyroclastic-flow eruptions; 6000 years ago.

Answer 1

4. Caldera collapse followed major ash and pyroclastic-flow eruptions; 6000 years ago.

Volcanic events formed Crater Lake was Caldera collapse followed major ash and pyroclastic-flow eruptions. It take place 6000 years ago.