Question

insert one comma to separate the coordinate adjectives. a reliable proactive employee, carly recently received a raise, along with an unexpected promotion to assistant store manager.

Explanation:

Coordinate adjectives modify a noun equally and can be joined with 'and'. Here, 'reliable' and 'proactive' are coordinate adjectives modifying 'employee'. A comma should be inserted between them.

Answer:

A reliable, proactive employee, Carly recently received a raise, along with an unexpected promotion to assistant store manager.