Given the demand equation 2x + 8p + xp = 90; where p is the price in dollars and 'x' is the quantity demanded (in thousands) of a certain commmodity. How fast the demand is increasing or decreasing at a time when x = 4, p = 10 and the price is rising at the rate $3 per week. The demand is decreasing at the rate 3000 units per week. The demand is decreasing at the rate 10 units per week. The demand is decreasing at the rate 10,000 units per week. O The demand is decreasing at the rate 3 units per week. O O O O