Which section includes tasks testing collocations and idiomatic expressions?

The correct answer is C, as the Reading and Use of English section is specifically designed to assess a candidate's understanding of lexical items, including collocations and idiomatic expressions. In this section, test-takers encounter various tasks that require them to demonstrate their ability to recognize, interpret, and effectively employ these phrases in context.

Collocations pertain to the natural combination of words that frequently appear together, while idiomatic expressions are phrases whose meanings are not immediately obvious from the individual words. Mastery of these language features reflects a deeper understanding of English that goes beyond basic vocabulary.

Other sections, such as listening, writing, and speaking, may incorporate exercises where idioms and collocations are relevant, but they do not focus specifically on these skills in the same comprehensive manner as the Reading and Use of English section, which explicitly tests candidates' grasp of these complexities in language use. Therefore, this section is crucial for evaluating proficiency in these specific areas.