The dog named Polo wiggled its tail when ________ saw the master coming.

Correct option is C

The correct option to fill in the blank is (c) It.

The pronoun used must agree with the subject, which is "The dog named Polo." Since the gender of the dog is not specified, the correct pronoun is "it", commonly used for animals unless their gender is emphasized.

Meanings of other options:

• She: (Hindi: वह) Refers to a female, which is incorrect as the gender is not mentioned.
• His: (Hindi: उसका) Refers to possession and does not fit as a subject pronoun here.
• They: (Hindi: वे) Refers to plural subjects, while "dog" is singular.

Corrected Sentence:
The dog named Polo wiggled its tail when it saw the master coming.

Example:

• itThe cat purred loudly when was petted.