Which of the following terms appear in the expansion of (x+y)^10? the letter "a" in each term represents a real constant.

Are there options for this?
because its says "which of the following"

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.