Fantastique Bikes is a company that manufactures bikes in a monopolistically competitive market. The following graph shows Fantastique's demand curve, marginal revenue curve (MR), marginal cost curve (MC), and average total cost curve (ATC).

Ithink it’s a but it might be wrong so sorry

Some connecting rods have to lubricate the cylinder wall or piston pin. the answer is letter d. graphite coating can be a major  additive to many  coating  systems and things such as connecting rods.  it functions as a refractory, lubricant, thermal conductor, and electrical conductor for a machine or thing to enhance its work.