No need explanation, just give me the answer pls
2. What is the most fundamental problem in planetary defense?
A. The fundamental problem is solving for the trajectories of NEOs to determine if they will impact Earth.
B. The fundamental problem is determining the mass and composition of NEOs so as to know if they impact Earth if they will pose a serious threat.
C. The fundamental problem is reaching NEOs with spacecraft.
D. The fundamental problem is diverting NEOs from intercept trajectories with Earth.
E. The fundamental problem is finding NEOs in time for defensive measures to be taken.