In the following passage, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank.

One day, a few hunters came into the forest and took the lion with them. They tied him up (1) ______ a tree. The lion was (2) ______ to get away and started to whimper. (3) ______, a mouse walked past and noticed the lion in trouble. He quickly ran and (4) ______ on the ropes to set the lion free. Both of them then (5) ______ into the jungle.

Select the most appropriate option to fill in blank number 4.