According to the speaker, what "has made all the difference" (line 20)?

He or she took the road that bent in the undergrowth.

He or she took the road less traveled by.

He or she took the first of the two roads.

The lines have been taken from the poem by Robert Frost the road not taken .This poems talks about the various choices that one encounters when  choosing a single life path and the significant changes that the choice he makes brings in his life.

Explanation:

The choice of choosing a path that is less traveled by is what made all the difference in the author's life.

The poems talks about a situation in the author's life in which he is confronted with a situation where he has to make a choice among the two paths .The narrator says that although both the path look similar but one of the path is going to decide the destiny of the poet.The term road refer to the choice one make in his life and the impact it has on their future is the main theme of the poem .

According to the speaker, what "has made all the difference"He or she took the road less traveled by.

the answer should be

the simple past tense of strive.

hope this !