Topic: Degree of Comparison,

Best Answer Explained in Below-:

The question "John is - than Rahim" requires an adjective that appropriately completes the comparison between John and Rahim in terms of age. Among the given options, "older" (C) is the most appropriate choice.

Firstly, "older" is the comparative form of the adjective "old," which is commonly used in comparative structures to indicate that one person has more years of age than another. The sentence implies a straightforward age comparison, making "older" the most natural and grammatically correct choice.

Considering the other options:
- "Elderly" (A) is an adjective describing someone advanced in age but does not serve as a comparative form and can sometimes carry a connotation of being frail or in need of care, which may not fit the sentence structure.
- "Senior" (B) can refer to someone in a higher position or older people in certain contexts, but it is not a comparative adjective for age that directly fits the structure of the sentence.
- "More aged" (D) is not commonly used in English to compare age. While grammatically it could work, it sounds awkward and less natural than “older.”

Thus, "older" (C) clearly provides a direct and effective comparison, making it the best choice for the sentence.