With the prom approaching, Carl wanted everything to be just right. One thing that was not “just right” was his complexion. Carl watched movie star after movie star on television talk about the great results they had when using Zero Zits blemish cream. Carl decided to try the product. He bought a tube and carefully followed the directions. With the prom only ten days away, Carl was hoping to look his best. The results of Zero Zits use can be seen in the graph. What is the MOST valid conclusion regarding Carl’s experience with Zero Zits?

A) Carl used the cream incorrectly.
B) The cream removed all of Carl's blemishes.
C) Carl's diet caused many more blemishes to develop.
D) Initially the cream seemed to work but new blemishes developed.