Answer: Rehearsal encoding
Explanation: Rehearsal is generally a repetition of something to remember and use later. This is also the case here when Randy repeated phone number repeatedly to memorise it until he found a pen to write it down. It is actually the transfer of information to memory that is facilitated by repeating the information until it is memorised. When it comes to transferring information into memory, there are two types of rehearsal, one is temporary rehearsal, which means retaining information in short-term memory, called maintenance rehearsal, and the other type is elaborate rehearsal, which is about storing learned information and linking it to already existing memories, hence in long-term memory. Here's a case where Randy kept repeating the number to remember it until he found the pen to write it down, so it's a short-term memory, and maintenance rehearsal.
