Read the excerpt from "Digging."

Till his straining rump among the flowerbeds
Bends low, comes up twenty years away
Stooping in rhythm through potato drills
Where he was digging.

Which statement best explains the effect of the word "straining” in this excerpt?

It emphasizes that working in fields is difficult and strenuous.
It draws attention to the speaker’s connection to the field.
It suggests that the father does not want to plant new potatoes.
It reveals that potatoes were the main crop of Ireland.