Step costs have no relation to number of units produced increase with each additional unit produced are variable within narrowly defined ranges of activity, but constant over wider ranges of activity are constant within certain ranges of activity but differ outside those ranges of activity Cari German uses gas to heat her home. She has accumulated the following information regarding her monthly gas bill and monthly heating degree-days. The heating degree-days value for a month is found by first subtracting the average temperature for each day from 65 degrees and then summing these daily amounts together for the month. MonthHeating Degree-days Gas Bill February1900$254 April600$101 What will be the increase in Cari's monthly gas bill per heating degree-day using the high-low method? $0.1177 $46.00 $0.3309 $153.00