Final answer:
A cashier at the supermarket should use her own 20% discount card, have another employee ring up the purchase, and pay for the soda before consuming it during her break, in compliance with the Personnel Policy.
Step-by-step explanation:
Under the Personnel Policy, a cashier at the supermarket should adhere to four key points when purchasing a soda to drink during her break. First, employees are entitled to a 20% discount, which the cashier can use for the soda purchase. Second, as discount cards are non-transferrable, the cashier must use her own discount card. Third, to comply with the rule that employees are not allowed to ring up their own purchases, the cashier should have another employee process the transaction. Finally, the policy states that employees must pay for food before consumption, which means the cashier needs to pay for the soda before starting her break.