When I do count the clock that tells the time

William Shakespeare, "Sonnet 12"
Why is this A. It has five metrical feet that each contain an unstressed syllable immediately followed by a stressed one.
B. It has four metrical feet that each contain a stressed syllable immediately followed by an unstressed one.
C. It has 10 unstressed words that sound as if they would be spoken by nobility.
D. It has 10 stressed syllables of equal importance.
s verse an example of iambic pentameter?