Lucy needs to buy some organic apples, and her grocery store is having a sale on them. if she buys 3 or fewer pounds of apples, the price will be $1.50 per pound. if she buys more than 3 pounds of apples, the price is $1.10 per pound. what is the domain of the piecewise-defined function, where  x  represents the number of pounds of apples? a. {x|  x  ≥ 0}b. {x|  x  is a real number}c. {x| 0 ≤  x  ≤ 3}d. {x|  x  ≥ 3}