Which Statistical test is it?

Any chance anyone knows the answer to this? I know it's not paired t-test but don't know which of the others it is

A hotel manager would like to test whether the average time taken for customers to complete the hotel's online booking form is less than 5 minutes. She selects a sample of 40 customer booking times. Which of the following is the most appropriate statistical test to use? Is it
1. Paired t-test
2. Independent samples t-test
3. One sample z-test
4. Independent samples z-test