Joelle plans to sell two types of balloons at her charity event: 17-inch latex balloons that require 2 cubic feet (ft^3) of helium and 18-inch mylar balloons that require only 0.5 ft^3. she only has access to 1,000 ft^3 of helium, 15% of which will be unused due to pressure loss in the tanks. she wants to have at least 500 balloons for sale in total. for the number of latex balloons, l, and number of mylar balloon, m, which of the following systems of inequalities best represents this situation? a. 0.5l + 2m ≤ 850 l + m ≥ 1,000 b. 2l - 0.5m ≤ 1,000 l - m ≥ 500 c. 0.5l - 2m ≤ 850 l - m ≥ 500 d. 2l + 0.5m ≤ 850 l + m ≥ 500