A word used to show the relationship between its object and some other word in the sentence is called a <em>preposition</em>. <u>The correct answer is the first one.</u>
Explanation:
A preposition is a word that governs or predicts a noun or pronoun and expresses its relationship to another word or element in the same clause. An example of this can be: "<em>The pencil is under the table</em>". In this example, the word <u><em>under</em></u> is a preposition that expresses its relationship with the element in the same sentence (<u><em>table</em></u>).
"b. Ben Bernanke became chairman of the federal reserve in 2006" is the only factual sentence from the options listed. The others are opinions or haven't happened yet.