Erudite1

The correct option is LOOKING UP THE ORIGIN OF UNFAMILIAR WORDS.
Close reading is the act of reading closely to determine what the text is saying explicitly and to make logical inference form it. To do this, one has to uncover layers of meaning that leads to deep comprehension. This will thus necessitate that one looks up the meaning of new words  and analyze how specific words impact on the meaning of the information that is been passed across in the text.