Explanation:

- Option 1: Extremely pale - This might describe someone looking very pale due to fear, illness, or shock, but it's not related to "in a nutshell."

- Option 2: Very briefly - This means summarizing something in a compact or concise manner. Much like a nutshell holds a nut, information is presented briefly.

- Option 3: Under protection - This phrase suggests being shielded or defended, but doesn't relate to summarization.

- Option 4: Without delay - This indicates doing something immediately, not linked to summarizing information.