Answer: Adele should have multiplied the total of all the choices.
Explanation:
Take the following as deciding factors:
BRAND: A or B
TRANSMISSION: 4-speed standard, 5-speed standard, or automatic
BUMPER: steel, vinyl, or 2x4 boards
ROOF: hard top or convertible top
Therefore, in other to calculate the possible vehicle choices available ;
BRAND variety ×TRANSMISSION variety × BUMPER variety × ROOF variety
2 × 3 × 3 × 2 = 36 possible choices.
Multiplying the option variety of each factor will allow for different combination of each of the option levels.