Answer:
The options are
A. autocrine signaling between tumor cells.
B. endocrine signalizing between tumor cells.
C. direct physical contact between tumor cells.
D. paracrine signaling between tumor cells.
The RIGHT ANSWER IS D.
D. paracrine signaling between tumor cells.
Step-by-step explanation:
Paracrine signaling is a type of cell-cell communication through which a cell gives a signal to cause changes in neighbouring cells, changing the behavior or differentiation of it's neighbouring cells.
Since, the tumor has to be localized in a small area of the body and cannot have metastasized (spread to other areas of the body). The new cancer drug would have to inhibit paracrine signaling between tumor cells.