A casual way to suggest making a final decision on which option to choose.
“Let's go with the second apartment — I really think it suits us better overall.”
“Let's go with the earlier flight so we have more time to settle in before the meeting.”
This is an excellent closing expression for Task 5, since the task ultimately asks you to commit to one option — using "let's go with" delivers a clear, decisive conclusion. Save it for your final sentence to leave the examiner with a strong, confident wrap-up rather than an open-ended answer.
Synonyms: let's choose, let's pick, let's decide on