There are generally more clouds near the oceans. Landlocked areas are usually at a lower altitude than coastline areas. Coastlines are usually surrounded by mountains that block air masses. Oceans change temperature slowly and regulate the temperature of nearby land.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Why do areas in the middle of a large continent generally have more extreme differences in temperature than areas near the coastline?
Possibilities:
- There are generally more clouds near the oceans.
- Landlocked areas are usually at a lower altitude than coastline areas.
- Coastlines are usually surrounded by mountains that block air masses.
- Oceans change temperature slowly and regulate the temperature of nearby land.

Oceans change temperature slowly and regulate the temperature of nearby land.