In the sentence "Coal is sometimes called stored-up sunlight", the italicized part is a(n)

A．This pair of trousers costs fifty dollars.
B．Either my grandsons or their father is coming.
C．The British police has only very limited powers.
D．A committee of twelve men is to discuss the matter.

A．It was Islamist radicals who attacked the center of Tripoli.
B．They saw security forces from the Interior Ministry there.
C．The deputy prime minister responded quickly online.
D．The protection from the government didn’t work.