Which of the following theorists identifies “metonymy” and “metaphor” as two fundamental structures of language?

The correct option is Roman Jacobson (commonly spelled Roman Jakobson).

Detailed Explanation:
In his seminal 1956 essay, "Two Aspects of Language and Two Types of Aphasic Disturbances", the Russian-American linguist and literary theorist Roman Jakobson proposed that language has a dual structure based on two fundamental operations: selection and combination. These two operations correspond directly to the figures of metaphor and metonymy:

1. The Selection Axis (Similarity / Metaphor):
This process involves choosing one word or sign from a group of similar options (e.g., choosing "child" instead of "kid", "youth", or "infant"). This axis operates on the principle of similarity and equivalence. Jakobson links this substitution process to metaphor, where one term is substituted for another based on likeness or analogy.

2. The Combination Axis (Contiguity / Metonymy):
This process involves combining the selected words into a linear sequence or sentence according to grammatical rules. It operates on the principle of contiguity (spatial, temporal, or logical connection). Jakobson associates this combination process with metonymy, where an association is made based on proximity or part-to-whole relationships (e.g., using "the crown" to refer to a monarch).

Jakobson argued that every speech action involves both selection and combination, and that any individual's use of language or literary style tends toward either the metaphoric pole or the metonymic pole. He demonstrated this by studying aphasia (language disorders), finding that patients typically suffer from either a "similarity disorder" (inability to use metaphors/selection) or a "contiguity disorder" (inability to construct sentences/combination).