🎥 Video solution / Text Solution of this question is given below:
Definition: An informal gathering occurs when a group of people get together in a casual, relaxed manner.
Check each option:
1) "After finding about his promotion, Jeremy and a few coworkers decide to go out for a quick drink after work."
- Small group of people ✔
- Casual and relaxed ✔
- Decided spontaneously, not formal ✔
→ This fits the definition of an informal gathering.
2) "Whenever she eats at the Italian restaurant, Kamalika seems to run into Peter."
- This is a chance meeting, not a planned get-together ✖
→ Not an informal gathering.
3) "The book club meets on the first Thursday evening of every month."
- Regularly scheduled and organized ✖
→ More formal, not purely informal.
4) "Mary sends out 25 invitations for the bridal shower she is giving for her sister."
- Planned event with invitations, quite formal ✖
→ Not an informal gathering.
Therefore, the best example of an informal gathering is <b>Option 1</b>.