10. None of the servants was ______ when Mr Smith wanted to send a message.

A. available B. approachable C. attainable D. applicable

<available>

available 可获得的，有用的

</available>

<approachable>

approachable 可接近的

</approachable>

<attainable>

attainable 可获得的

</attainable>

<applicable>

applicable 可应用的

</applicable>