Answer:
A. Omit the apostrophe in the father's.
Explanation:
You want a plural form here rather than a possessive form.
B. is the BEST because it gives the flexibility of theme ideas for courage.
C. is very specific on climbing mountains as the only way to learn about courage.
A and D are criticising courage.
C. Generally, an intensive pronoun comes after the subject of the sentence, and in this case, it comes after "the girl", which is the subject.