Concept:
- Homophones are words that sound exactly the same when spoken but differ in spelling and meaning.
Step 1: Say each pair out loud and compare the sound
'Cell' and 'Sell' are both pronounced the same way, only the first letter sound differs in spelling, not in the actual spoken sound.
Step 2: Check the remaining pairs
'Ball' and 'Bell' have different vowel sounds. 'Fan' and 'Fun' have different vowel sounds. 'Fall' and 'Full' have different vowel sounds. None of these are pronounced identically.
Step 3: Conclude which pair qualifies as homophones
Only 'Cell' and 'Sell' sound identical, making them true homophones.
Final Answer: Cell - Sell