What are the smallest units of sound that create differences in meaning?

Question

Quizplus · Accepted Answer

Phonemes are the smallest units of sound in a language that can create differences in meaning between words. For example, the difference between the words "cat" and "bat" is only one phoneme (/k/ versus /b/).

B) Morphemes are the smallest units of meaning in a language, but they do not necessarily create differences in meaning between words. For example, "unhappy" and "happily" have different morphemes (-un versus -ly) but they do not have different meanings.
A) Holophrases are one-word sentences used by infants or in certain languages where a single word can convey an entire phrase or sentence. 
D) Prosodies refer to the patterns of stress, intonation, and rhythm in speech that can convey meaning, but they are not considered the smallest units of sound that create differences in meaning between words.

What Are the Smallest Units of Sound That Create Differences