Answer: The answer is Phonology
Step-by-step explanation:
The definition of Psycholinguistics is the study of the relationships between linguistic behavior and psychological processes
So that's not right
The definition of Morphophonemics is a study of the phonemic differences between allomorphs of the same morpheme.
So that's not right either
The definition of Phonetics is the study and classification of speech sounds
And this matches what we are looking for, to we don't have to check phonology