Answer:
The option that would correctly complete the sentence is D.Jack's.
<em>Because he has to take care of the animal, it will be </em><em>Jack's</em><em> decision. </em>
Explanation:
In English, <u>the possessive case ('s)</u> is used for showing possession or ownership. An apostrophe and the letter <em>s</em> are introduced after a noun or pronoun to express that a person, place, or thing owns another.
In the case of this sentence, one can say that the pronoun or noun that needs to be introduced is singular -because of the reference to the pronoun <em>he</em>. <em>Jack </em>is the noun in singular form, and one should add the <u>possessive case ('s) </u>to show "possession" of the decision. Therefore, option D. Jack's is the correct answer.
