Final answer:
The 0.88 in the equation c=0.88a represents the cost of one avocado.
Step-by-step explanation:
The 0.88 in the equation c=0.88a represents the cost of one avocado. It tells us that for every avocado purchased, the cost will be 0.88 dollars. Therefore, option a, 'Cost of one avocado', is the correct answer.