The following information is available for Martha, a sole trader who does not keep full accounting records: $ Inventory January 1, 2020 138,600 Inventory December 31, 2020 148,100 Purchases made for the year ended December 31, 2020 715.100 Martha makes a standard gross profit percentage of 30% in sales Based on these figures, what is Martha's sales figure for the year ended December 31, 2020? Select one: O a $1,008,000 O b. $1,038,000 Oc. $917.280 O d. $2.352,000