THIRD option is correct I think.Hope it helps.
Answer:
not discovered or known about; uncertain.
keep from being seen; conceal.
One way to vary the syntax of the text is to combine sentences since, in this way, your structures will be longer and more complex to follow. This could be done by means of links such as: however, in addition, therefore, etc. When using these words, you create semantic relations between the syntactic structures and make the reading process more difficult because, as I've I said, sentences become longer and therefore the reader has to keep more information in mind to follow the train of thought.
You could also vary the syntax by adding phrases or clauses. This option is similar to the previous one since it also refers to the complexity of the syntactic structures of the text.
Hemingway compares Santiago and Jesus Christ in the described scene. The wounds on the forehead and the arms are combined with the skiff carrying that resembles Jesus carrying his own cross.