In the "Pulse-Chase" Experiment, Palade and Colleagues Studied the Pathway $\rightarrow$

In the "pulse-chase" experiment, Palade and colleagues studied the pathway taken by newly secreted proteins in pancreatic acinar cells by labeling them with radioactive amino acids, removing unused label, and determining their location within the cells at various time points. Which sequence represents the correct order in which the proteins were identified?

A) Secretory vesicles $\rightarrow$ Golgi apparatus $\rightarrow$ rough ER $\rightarrow$ nucleus
B) Golgi apparatus $\rightarrow$ rough ER $\rightarrow$ nucleus $\rightarrow$ secretory vesicles
C) Rough ER $\rightarrow$ secretory vesicles $\rightarrow$ Golgi apparatus
D) Rough ER $\rightarrow$ Golgi apparatus $\rightarrow$ secretory vesicles