78.
A:
An acceptance may be revoked at any time before the communication of the acceptance is complete as against the proposer, but not afterwards.
B:
An acceptance may be revoked at any time before the communication of the accpetance is complete as against the acceptor, but not afterwards.
C:
An acceptance may be revoked at any time before the communication of the accpetance is incomplete as against the acceptor, but not afterwards
D:
An acceptance may be revoked at any time after the communication of the acceptance is complete as against the acceptor, but not afterwards.
The answer is: B
