Answer:
Running into an old friend who is in town for one day.
Explanation:
The term "fortuitous" refers to a chance occurrence, a surprising and unexpected event that happened, a fortunate event. This word is used to talk about things that happened unplanned and completely unexpected.
A fortuitous event means an event that happened so suddenly and unexpectedly that it leaves you shocked and completely unforeseen. Such an event is wholly unexpected and surprising. So,<u> running into an old friend who's in town for a single day is a fortuitous event</u>, for it is a chance encounter and not something that happens often or even planned.
Thus, the correct answer is the last/ fourth option.
