Since the old lady’s husband died, she’s been living _______-.
( Fill in the blank with the most appropriate word.)
a. herself
b. by herself
c. by itself
d. by her

Hint: Read the given sentence and decipher what it means. Now go through the options carefully after reading the sentence and select the one which best expresses what the sentence wants to convey.

Complete answer: In this question, it will be helpful for the student to recall the concept of reflexive pronouns. A reflexive pronoun is a personal pronoun compounded with -self to show that the agent's action affects the agent.
Let us analyze the options given to us in this question -
Option (a.), 'herself', is incorrect as it does not suggest that the old lady started to live alone ever since her husband died.
Option (b.), ‘by herself',.) is correct as it employs the right reflexive pronoun ‘herself’ as the subject, the ‘old lady’ is a feminine subject and the usage of ‘by’ indicates that she did live alone.
Option (c.), ‘by itself', refers to ‘itself’ as the reflexive pronoun.
Therefore, option (c.) is incorrect as ‘herself’ is right reflexive pronoun as the subject, the ‘old lady’ is a feminine subject while ‘itself’ is used for ‘it; A thing as the object of a verb or preposition that also appears as the subject’.
Option (d.), ‘by her', refers to ‘her’ for the pronoun.
Therefore, option (d.) is incorrect as a reflexive pronoun is supposed to be employed here, not a personal pronoun.
Therefore, option b. is correct.

Note: Reflexive pronouns, like myself, himself, herself, itself, themselves, ourselves, yourself, yourselves etc should be used only when they refer back to another word in the sentence. (A reflexive pronoun reflects the action described by the verb.)