Question

1. which punctuation cannot be used in place of an em dash?

commas
colons
parentheses
periods

Explanation:

An em dash is used for emphasis, interruption, or to set off additional information. Commas, colons, and parentheses can sometimes be used in similar contexts (e.g., commas for a less strong break, colons for introducing info, parentheses for parenthetical info). However, a period is used to end a sentence, which has a very different function from an em dash (which is used within a sentence), so it cannot replace an em dash.

Answer:

D. periods