How u do this :( also what subject is this

Interpret An electric company charges a certain rate per kilowatt- hour (kWh) of electricity used and an administrative fee of $3.50. The company charged Zhao $63.25 for using 800 k Wh of electricity. Zhao uses the equation, 63.25 = 800r + 3.50 to represent the situation. What does the variable r represent in the equation? Choose 1 answer: A The number of kilowatt-hours Zhao used B The charge per kilowatt-hour The amount of the total charge that depends on the C number of kilowatt-hours used ChAn electric company charges a certain rate per kilowatt- hour (kWh) of electricity used and an administrative fee of $3.50. The company charged Zhao $63.25 for using 800 k Wh of electricity. Zhao uses the equation, 63.25 = 800r + 3.50 to represent the situation. What does the variable r represent in the equation? Choose 1 answer: A The number of kilowatt-hours Zhao used B The charge per kilowatt-hour The amount of the total charge that depends on the C number of kilowatt-hours used