Context clues can be used to understand words you don't understand. true or false

Read this sentence from the story of my life by helen keller. the most important day i remember in all my life is the one on which my teacher, anne mansfield sullivan, came to me. which element of plot does this sentence best represent?

(1) fire extended humans’ geographical boundaries by allowing them to travel into regions that were previously too cold to explore. (2) it also kept predators away, allowing early humans to sleep securely. (3) fire, in fact, has been a significant factor in human development and progress in many ways. (4) other obvious benefits of fire are its uses in cooking and in hunting. (5) probably even more important, however, is that learning to control fire allowed people to change the very rhythm of their lives. (6) before fire, the human daily cycle coincided with the rising and setting of the sun. (7) with fire, though, humans gained time to think and talk about the day’s events and to prepare strategies for coping with tomorrow. the sentence that expresses the main idea is: (type the number of the sentence. then click “go.”)

Which sentence uses all its nominative case pronouns correctly? a we live on the same street b them and rachel are good skaters. c the redskins fans in the family are fred and me d have joanne and him played tennis together before?