What's different between the RACH $$ Random Access CHannel versus the AGCH $$ Access Grant Control CHannel?

Group of answer choices

With AGCH the phone sends information to the tower, with RACH the tower is sending information to the phone

They're on the same frequency but use different encoding

With RACH the phone sends information to the tower, with AGCH the tower is sending information to the phone.

Nothing; they are both part of Common Control Channels $($CCCHs$)$