Which of the following is true about the demand curve?

A、Itisusedtoillustratetheeffectofpriceonthequantitysupplied.
B、Itisalwaysgraphicallydepictedbyastraightline.
C、Itshowsthequantityofproductcustomerswillbuyinamarketduringaperiodoftimeevenifotherfactorschange.
D、Itusuallyslopesupwardandtotheright.
E、Itshowstherelationshipbetweenproductdemandandproductprice.