Correct Answer: Only four
Explanation:
Iran shares land borders with the following countries:
Turkmenistan:
- Yes, shares a land border with Iran in the northeast.
 
Turkey:
- Yes, shares a land border with Iran in the west.
 
Syria:
- No, does not share a land border with Iran. Syria is separated from Iran by Iraq.
 
Lebanon:
- No, does not share a land border with Iran. Lebanon is located farther west.
 
Afghanistan:
- Yes, shares a land border with Iran in the east.
 
Israel:
- No, does not share a land border with Iran.
 
Azerbaijan:
- Yes, shares a land border with Iran in the northwest.
 
Countries Sharing a Land Border with Iran:
- Turkmenistan
 - Turkey
 - Afghanistan
 - Azerbaijan
 
Conclusion:
Iran shares a land border with four countries: Turkmenistan, Turkey, Afghanistan, and Azerbaijan.
Thus, the correct answer is Only four.