Scenario Biomedical Scientists Have Recently Developed an Anticancer Drug Delivery System

Scenario
Biomedical scientists have recently developed an anticancer drug delivery system that sneaks the anticancer drug into cancer cells before releasing it. They were able to do this by using two sets of liposomes. An anticancer drug (Doxorubicin (Dox) ) bound to DNA molecules was added into one set of liposomes, and a high concentration of ATP molecules were added to the other set of liposomes. The drug is inactive when bound to DNA molecules. Researchers inject both types of liposomes into cancer cells, and upon doing so their contents are released. The ATP molecules from one set of liposomes bind to the DNA molecules from the other set of liposomes) and activate the drug, thus inducing cell death and decreasing tumor size.
Mice with breast cancer tumors were treated with this liposome system to test the effectiveness of the drug. The scientists performed three trials-one with both types of liposomes (Dox + ATP) , one with just the drug (Dox only) , and one with a salt solution (control) . Examine the figure below and answer the following questions.
-A student in your class examines the graph and hypothesizes that ATP is what kills cancer cells, and not Dox. What follow-up experiment would allow you to test this student's hypothesis?

A) Add a fourth trial, in which mice with breast cancer tumors are treated with liposomes containing just ATP (ATP only) .
B) Repeat the three trials described in the scenario until the tumor weights are the same from treatments with just Dox (Dox only) and both types of liposomes (Dox + ATP) .
C) Treat mice with breast cancer tumors with liposomes containing both Dox and ATP together (not in separate liposomes) .
D) Observe what happens to mice when ATP and Dox are combined in the absence of tumors.