Answer:
a. Gestalt
Explanation:
Gestalt, Gestaltism, or Form Psychology is a doctrine of psychology based on the idea of understanding wholeness in order to perceive parts. Gestalt is a word of Germanic origin, with an approximate translation of "form" or "figure".
Gestalt theory, also known as Gestalt Psychology or Good Form Psychology, is part of the studies of human perception, which began to develop between the late nineteenth and early twentieth centuries. The pioneers of this doctrine and formulators of the Gestalt Laws were psychologists Kurt Koffka, Wolfgang Köhler, and Max Werteimer.
The Gestalt emerged as a doctrine of opposition to Atomism, a philosophy that believed it was possible to perceive the whole only after understanding the different parts.
Therefore, we can say that a person who speaks "I believe that mental experience is best understood as a whole, rather than in terms of its parts." accepts the concepts regarding Gestalt.