Allied to the point that the offeror can prescribe a particular method of acceptance the offeror can also stipulate the time within which the acceptance must be communicated. This can, of course, be an express stipulation but it might also be implied from the method used in communicating the offer. For example, if the offer is sent by telegram this would imply that the acceptance had to be by an equally fast means of communication.
NB Generally the mode of communication of the offer only fixes the time within which the acceptance must be communicated. It does not fix the actual method of communication to be used.