Choose the multiplication problem that matches this model: I Dan studied for of an hour for 4 days in a row. How many hours did he study? Dan studied for 2 hours for 4 days in a row. How many hours did he study? O Dan studied for of an hour for 4 days in a row. How many hours did he study? O Dan studied for of an hour for 4 days in a row. How many hours did he study?