They are looking for those employees with a high level of ............. in English. A. expansion     B. settlement     C. proficiency

The correct answer is C. proficiency.

The phrase "high level of ..." typically refers to a skill or expertise in a particular area. In this case, they are looking for employees with a high level of proficiency in English. "Proficiency" means the ability to perform effectively and skillfully in a particular subject or skill, which in this case is the English language.

The other options do not fit in this context. "Expansion" refers to the process of increasing in size or scope, and "settlement" typically refers to the act of establishing a residence or resolving a dispute. Neither of these terms relates to language skills or abilities. Thus, the most appropriate choice is "proficiency."