Answer: B. The enslavement of the Israelites in Egypt
Explanation: Moses saved the Israelites, as it is believed, by taking them out of the Egyptian bondage, giving them the Ten Commandments of God, leading through the desert, which meant the purification of the chosen people from sin and led them to the promised land. This deliverance from bondage has a twofold dimension, a deliverance from physical bondage, the first one, then the Ten Commandments and wandering through the desert for the sake of purification, a spiritual dimension, second one. Moses himself did not enter the promised land, because there near Canaan he carried out his mission.
The swarms of the locusts and flies in Egypt was one of the means God gave Moses to persuade Pharaoh to free the Jews.
The move from Ur to Canaan is related to Abraham much earlier than Moses and much earlier before the Israelites even found themselves in Egypt.
The flooding caused by rain, which lasted 40 days and 40 nights, happened much earlier before all of this, and refers to Noah, the righteous one whom God chose to survive a great flood by telling him to build a large ship and thus save himself and his family and two animals, male and female of every kind.