A van hire firm works out the cost with the rule C = 0.42d + 35, where C is the cost in pounds and d is the distance driven in kilometres. What does the 35 stand for?

1. In a rule of the form output = rate times input plus starting value, the number added on its own is the starting value. 2. Setting d to 0 kilometres leaves C = 35, so 35 pounds is charged before a single kilometre is driven. 3. The 0.42 is the amount added for each kilometre, so option B swaps the two numbers round. 4. So the 35 is the cost before any distance is driven, option A. _Source: OpenStax College Algebra (CC BY 4.0), Ch 4 "Linear Functions", section 4.1 Linear Functions_