Now it is ten o'clock ____ my watch .
A
from
B
by
C
at
D
of
Correct Answer: by
A preposition is a word which comes before a noun or a pronoun and establishes a relationship between the elements of a clause or words. Option by is correct as it indicates an agent. The other options are wrong as from, at, and of indicate the inside of something, a specific location, and a direction respectively. These uses don't fit in the given question. The correct answer is by.