Choose the correct passive form of the sentence.
People regard the ancient manuscript as one of the most important discoveries of the century.
AThe ancient manuscript is regarded as one of the most important discoveries of the century.
BThe ancient manuscript was regarded to be one of the most important discoveries of the century.
CThe ancient manuscript is regarding as one of the most important discoveries of the century.
DThe ancient manuscript has regarded as one of the most important discoveries of the century.
