A Researcher Has Arrived at a Method to Prevent Gene

Multiple Choice

A researcher has arrived at a method to prevent gene expression from Drosophila embryonic genes. The following questions assume that he is using this method.
-The researcher measures the concentration of the polypeptides from different regions in the early embryo and finds the following pattern (darker shading = greater concentration) :

Which of the following would be his most logical assumption?

A) The substance has moved quickly from region 5 to region 1.
B) Some other material in the embryo is causing accumulation in region 1 due to differential binding.
C) The cytosol is in constant movement, dispersing the polypeptide.
D) The substance is produced in region 1 and diffuses toward region 5.
E) The substance must have entered the embryo from the environment near region 1.