See the explanation as given below.
Work Step by Step
Let $x$ be the manufacturing cost.The fixed cost of a phone is $200,000$. During each bicycle it costs $250$. Selling price per phone = 300 Cost function $C(x)=200,000+250x$ Here, $200,000$ refers to the first cost overhead cost of the company and $250x$ will be the second cost will be used to manufacture each new phone.