Many mixed drinks (long island iced tea, margaritas, etc.) have increased amounts of and one of these drinks may equal two, three, or more of a standard drink. the combination can decrease the perception of the driver.
a.) alcohol
b.) calories
c.) proteins
d.) caffeine

a.) Alcohol

Explanation:

Long Island Iced Tea is a combination of different alcoholic drinks like tequila, vodka, and sour mix with a small amount of cola and lemon juice that intoxicates quickly. It is a type of drink that does not contain tea even though from its name, it can be said to contain tea. It is usually garnished with a lemon wedge and served with ice.

Margaritas is also a combination of tequila, vodka, sour mix with lime juice and sugar. Both Long Island Iced Tea and Margaritas contain a high level of calories and can increase weight gain if one does not exercise often.  So, the combination of both Long Island Iced Tea and Margaritas have a large amount of alcohol which is beyond the standard of a normal drink.  These combinations can decrease the perception of a driver.

sadly i believe the answer is d