Which of the following phrases should be added to the phrase “Ben completed the project on time to show a cause and effect interaction

as a result

To show a cause and effect interaction in the phrase "Ben completed the project on time," you can add the following phrase:

"as a result"

To identify a cause and effect interaction, you can add the phrase "as a result" to the sentence. Thus, the revised sentence would be: "Ben completed the project on time, and as a result, he impressed his boss."

By including the phrase "as a result," it indicates that completing the project on time had a specific outcome, which is impressing the boss.