Concept:The correct word must show that both tasks were done at the same time to allow an early finish.
Explanation:If the tasks were done together, time is saved, so they could finish early.
"Simultaneously" means at the same time.
"Alternatively" means one instead of the other.
"Consecutively" means one after the other.
"Separately" means not together.
Therefore, "simultaneously" fits the sentence best.
Answer:B. simultaneously
"The two tasks were performed simultaneously and we were able to finish early."