Answer:
Traveling inch by inch
Step-by-step explanation:
The words that create suspense in the given passage are traveling inch by inch. Rainsford is watching General Zaroff from a tree and trying to remain discreet. He wants to attack, but doesn't, as he sees that Zaroff has a gun. At the end of the passage, Zaroff begins to look up the tree inch by inch. This creates suspense. It's an action that takes longer than it should (Zaroff could've looked at the tree quicker), which makes us nervous about what is going to happen next, about whether he is going to see Rainsford or not.
The rest of the options are just words that make it easier for us to imagine the scene more vividly.