Final answer:
The best data type to hold the value "greetings" is a string since it is used to store textual content.
Step-by-step explanation:
The value "greetings" is textual content, and in most programming languages, textual content is stored as a string data type. This means the correct answer is (a) string. Unlike other data types such as integers which store numbers without decimals, floating-point which store numbers with decimals, or boolean which store true or false values, strings are used to store characters, words, or any sequence of text.