Answer:
Although, some components of the question is missing, but the answer is D
Step-by-step explanation:
Although, the lesson being referred to in the question isn't stated, however, competitions cannot be regarded to be harmful to a person's self-esteem. Individuals involved in competitions are rather seen to be courageous and become known, at the very least, among there peers.
Competitions in most cases lift individual's pride, even during defeat, so far effort is made, hence lifting the self-esteem of the individual as many people will rally round and encourage such individuals. Also, since competitions aren't always against other people, it is wrong to state that competitions are harmful to a person's self-esteem.