R. Williams Company experienced the following selling expense and sales volume activity during the past year: Month Sales Selling Expense January $2,100,000 $210,000 February 2,400,000 220,000 March 1.900.000 200.000 April 1,700,000 195,000 May 1,600,000 180.000 June 1,900,000 212.000 July 2,200,000 220,000 August 2,600,000 250,000 September 2,300,000 248,000 October 2,100,000 235,000 November 1,800,000 210,000 December 2,000,000 215,000 Using the "hi-low" method, the fixed and variable parts of selling expense for R. Williams Company respectively are: O $68,000 and $.07 per sales dollar. $232,500 and $.07 per sales dollar. O $1,500,000 and $4.00 per sales unit. O $250,000 and $.20 per sales dollar