Step 1: Focus on the exact meaning.
The phrase asks for the word meaning "fit or safe to drink", which is a very specific sense distinct from being fit to eat.
Step 2: Recall the correct term.
"Potable" means fit for drinking, most commonly used in the phrase "potable water", and this matches the phrase exactly.
Step 3: Rule out the other options.
"Edible" and "eatable" both mean fit to be eaten, not drunk. "Palatable" means pleasant to taste, which is about flavor, not about being safe to consume as a liquid. "Perishable" means likely to decay or spoil quickly, unrelated to drinking.
Step 4: Select the answer.
The word that specifically means "can be drunk" is "potable", option (c).