Answer: Chunking method
Step-by-step explanation:
Chunking technique is defined as the method in which a person tends to take smaller piece or units of information known as chunks and gathering it to make a large information unit.This helps in remembering the information that cannot be learned and remembered as a whole.
According to the situation mentioned in question,Vikranth is using chucking method.He memorizes the letters in the form of small groups by tricking it with his friend's names.This make it easy to remember letter's long strings an improves memorizing power.