Acronyms use of each word in a phrase
a.
first two letters
c.
last two letters
b.
last letter
d.
first letter

The answer is D: the first letter.

An acronym is a name or a word that is formed like an abbreviation but that it only incorporates the initial components of a phrase, usually and most frequently the first individual letters (although sometimes they may incorporate the initial syllables; there are no strict and well defined rules on how to create an acronym, however, they can usually be read phoneetically in an easy manner).

An example of an acronym would be NAFTA (North American Free Trade Agreement) which, as can be seen, only incorporates the first letter of each word considered.

d

explanation: