All of the statements are true.The reason being :
Statement 1 is true because the schedule is 2PL serialisable only if there is no conflicting locks..All locks should be acquired accourding to the lock points defined..Else it is not allowed by 2PL thus ensuring serialisablilty in this way..
Statement 2 is true as the requirement of 2PL says this that unlock should be preceded by locks..
Statement 3 is true as the data transactions (reads and writes) are allowed after locks are acquired successfully else not..
Hence all statements are true..