Which of the following would be a clear violation of anti$-$trust law in the U$.$S$.?$

Executives of two competing companies in the same industry discuss their pricing strategy during a round of golf and create a gentleman's agreement to follow the same pricing strategy.

Executives of two competing companies in the same industry discuss the possibility of a merger between the two companies over cocktails and dinner.

A company aggressively pursues mergers and acquisitions with competitors and possible suppliers in an effort to increase market share.

A restaurant engages in price discrimination by offering college students $20\%$ off lunch on every Tuesday.