help plz

Company A's gross profit rate last year was 32.0% and this year it is 28.4%. Which of the following would not be a possible cause for this decline in the gross profit rate? Company A's average margin between unit selling price and inventory unit cost is decreasing. Company A may have seen a decline in total gross profit white maintaining net sates. Company A may have begun selling products with a higher markup. Company A must have pald higher prices to suppliers without passing these costs on to customers