In March 2014, a gas company had the rate schedule shown to the right for natural gasusage in single-family residences.(a) What is the charge for using 30 therms in a month?(b) What is the charge for using 200 therms in a month?(c) Develop a function that models the monthly charge C for x therms of gas.(d) Graph the function found in part (c).Monthly service chargeDelivery chargeFirst 40 thermsOver 40 thermsNatural gas costFirst 40 thermsOver 40 therms$18.35$0.84327/thermSO$0.3306/therm$0.5122/therm