Look at the equations and see if the statements are true.
Company 1 and 4 do not charge the same rate per mile, company one charges 0.5 per mile and company 4 charges 0.06 per mile.
Company 2 and 3 do not charge the same.
Company 2 has an x in the equation so is not just a flat fee.
Company 3 does not have an x in the equation, so only charges a flat fee.
The correct answer is the last one.