Final answer:
The customer pays $5.00 for each gigabyte of data used under the $10 monthly data plan, as the cost of the plan is divided by the amount of data used (2 GB).
Step-by-step explanation:
To determine how much the customer pays for each gigabyte of data under the phone company's plan, we simply divide the total monthly cost of the plan by the number of gigabytes used. Since the plan costs $10 per month and the customer uses 2 GB of data, the cost per gigabyte is calculated as follows:
$10 per month ÷ 2 GB = $5.00 per gigabyte.
Therefore, the customer pays $5.00 for each gigabyte of data used, which corresponds to option B. $5.00.