Please help. Read the sonnet.

"Sonnet 12" by William Shakespeare

When I do count the clock that tells the time,
And see the brave day sunk in hideous night;
When I behold the violet past prime,
And sable curls all silvered o'er with white;
When lofty trees I see barren of leaves
Which erst from heat did canopy the herd,
And summer's green all girded up in sheaves
Borne on the bier with white and bristly beard,
Then of thy beauty do I question make,
That thou among the wastes of time must go,
Since sweets and beauties do themselves forsake
And die as fast as they see others grow;
And nothing 'gainst Time's scythe can make defence
Save breed, to brave him when he takes thee hence.
Which characteristic of "Sonnet XII" shows that the poem is a sonnet?

A. It has fourteen rhyming couplets.
B. It has three quatrains and one rhyming couplet.
C. It has three rhyming couplets and one quatrain.
D. It has six rhyming couplets.

And please don't answer for just the points.