Label the parts of speech in the sentence; emily is always careful with tania's stuff.

Emily: noun (a noun could be the name of a person, thing, place, etc. In this case is the name of a person).

is: verb (it express action)

always: adverb (an adverb is a modifier of a verb, an adjective or another adverb. In this case, it is modifying the word "careful").

careful: adjective (an adjective modifies or describes a noun or a pronoun. In this case it is describing Emily, which is a noun.)

with: preposition (a preposition is placed before a noun or a pronoun to modify the phrase. In this case it is placed before the noun "Tania").

Tania: noun (The name of a person).

's: Possessive adjective (modifies the noun "Tania").  

stuff: noun (the name of a thing).

the tone of the passage is sympathetic to the forbidden love of romeo and juliet. the nurse plays a significant role in the play. she is responsible for making their meeting again possible. additionally, there is a sense of warning in the choice of words of the nurse. she seems to be authoritative when she calls romeo "scurvy knave", and at the same time the fact that she addresses to him as "sir" reflects respect. the nurse is "vexed", this word describes her confused state of mind. on the one hand, she finds romeo a fine and eloquent man, but on the other, it is thought that man's nature forces men to try to trick women.  

i think it may be b, i'm not exactly too sure on this. but b seems to make more sense.