Step 1: Understand the question.
What control does the Contiguous Zone allow a coastal state to exercise?
Step 2: Recall the zone.
The Contiguous Zone extends up to 24 nautical miles from the baseline, just beyond the territorial sea.
Step 3: Note the limited power.
Here the state does not have full sovereignty. It can only act to prevent and punish breaches of its customs, fiscal, immigration, or sanitary laws.
Step 4: Eliminate the others.
It cannot claim full airspace sovereignty here, cannot mine the deep ocean floor in this zone, and cannot stop the innocent passage of foreign ships.
Step 5: Conclude.
The state can prevent infringement of customs, fiscal, immigration, or sanitary laws.
Answer: Prevent infringement of customs, fiscal, immigration, or sanitary laws.