"a sentinel at each end of the bridge stood with his rifle in the
position known as 'support,' that is to say, vertical in front of the left
shoulder, the hammer resting on the forearm thrown straight across the
chest -- a formal and unnatural position, enforcing an erect carriage of
the body
what is the meaning of the word sentinel as it is used in this sentence
from the passage?
a)
a feeling of emotion
b)
a man who stands guard
c)
a place for tools
d)
a support for a rifle

B) a man who stands guard

Explanation:

In this passage, the word "sentinel" is used to indicate a "man who stands guard" and this is clearly conveyed in the text.

It cannot be "a feeling of emotion", "a place for tools" or "a support for a rifle", because we can figure out from the text that it's about a person, not an object or a feeling. We can read about this person's forearm and chest - "the hammer resting on the forearm thrown straight across the chest".

This person is guarding something or someone -> "at each end of the bridge stood with his rifle in the position known as 'support'", so it's a man who stands guard.

the third answer is right : )

i hope this you with your work! : )