Final answer:
The club sponsor should provide each patron with a handwritten receipt on school letterhead as documentation of their donation and then deposit the monies collected.
Step-by-step explanation:
The acceptable procedure for handling funds collected during the car wash would be option B. The club sponsor should provide each patron with a handwritten receipt on school letterhead as documentation of their donation and then deposit the monies collected. This ensures transparency and accountability as it provides evidence of the funds collected and their intended purpose.