love and sacrifice for others is the highest virtue.
The story "The Gift of the Magi" highlights the theme of unconditional love that is beyond the materialistic happiness. Della and Jim bought materialistic gifts for each other on the cost of their most loved things. Although the gifts they received were of no use but the sacrifice that they gave to bring happiness in other's life was worth it. They were ready to sacrifice and give up the best things they had for themselves to make the other happy. This is the major theme of the story.
"Keep", "factor", and "calculate" are all verbs in the list of things the new system allows teachers to do. The other sentences are inconsistent with their list of verbs/adjectives/nouns. Thus, option D is the only one that is grammatically correct.
I am not too good at explaining, so let me know if you are still confused.
Omit unnecessary words and phrases: excessive adverbs and adjectives detract from the formality of writing, as do phrases such as "you know", and "like" and "well" at the start of sentences, or during pauses in the sentence's rhythm. 4.