Engine 4 is responding to a fire in a commercial building with a base flow of 1,000 gallons per minute (gpm). There are two buildings within 50 feet from the fire building. For the Company Officer (CO) to make the most accurate decision on the number of handlines and personnel needed to extinguish the fire, they must determine the correct fire flow, including the fire flow needed for buildings with exposures. How much total fire flow is required in this situation? 1,500 gpm. 2,100 gpm. 500 gpm. 1,000 gpm