Answer:
single
Explanation:
In sentence one, the verb <em>single out</em> means to separate or choose something or someone from others in a group. Thus, the customs officer separated two people from a group.
In sentence two, the noun <em>single </em>refers to a music CD, record or cassette which contains one or two songs. In that matter, the artist had good reviews but fans did not like it.
Finally, in sentence three, the noun <em>single </em>means that the man is not married. As a result of his mother's annoyance, Russell enjoyed being single and did not get married until he was forty-five.
