What is the meaning of the word casually in this paragraph

What is the meaning of the word casually in this paragraph?

in a shy and quiet way

in a loud and showy way

Chris wanted to sit next to the stars of his

school's baseball team, but he wanted to

treat them like his other friends. As he

passed their table, he acted cool and

casually acknowledged their presence.

Chris' natural behavior won him the

friendship of the baseball team. They

always looked forward to hanging out with

kids like Chris, who didn't treat them any

differently than the rest of the students.

in a serious and formal way

in an informal or natural way

Answer: in an informal or natural way.