Step 1: Understanding the Concept:
This question tests pronoun choice ("those" vs. "the ones"), relative pronouns ("who" vs. "that"), and idiomatic constructions ("ability to" vs. "ability of").
Step 2: Detailed Explanation:
Pronoun Choice: When referring to people in a general sense, "those" is generally preferred over the more informal "the ones."
Relative Pronoun: When referring to people, the relative pronoun "who" is preferred over "that."
Idiom: The correct idiom is "the ability to do something" (using an infinitive). The construction "the ability of doing something" (using a gerund) is unidiomatic and incorrect.
Let's analyze the options based on these rules:
(A) Uses "the ones," "that," and the incorrect idiom "ability of settling."
(B) Ungrammatical. "Them" cannot be the subject.
(C) This is the correct answer. It uses the preferred pronoun "those," the correct relative pronoun "who" for people, and the correct idiom "ability to settle."
(D) Uses "that" instead of the preferred "who." The placement of "even" is also slightly less natural.
(E) Uses "the ones" and the incorrect idiom "ability of... settling."
Step 3: Final Answer:
The best construction uses "Those" to refer to the negotiators, "who" because they are people, and the idiom "ability to settle." Option (C) meets all these criteria.