Final answer:
The indirect object in the sentence is 'kiss'.
Step-by-step explanation:
In the sentence, 'The beautiful young princess gave the kiss so he could become a prince,' the word 'kiss' is the indirect object.
The indirect object is the person or thing to whom or for whom the action is done. In this sentence, the princess gave the kiss, and the person receiving the kiss is 'he,' who could become a prince.
Therefore, the correct answer is option B: kiss.