The correct answer is: A. Both 1 and 2 are true.
A continuous-time linear time invariant (LTI) system is said to be BIBO stable if the output remains bounded for all bounded inputs. The system is said to be causal if the output does not precede the input.
The poles of a system are the roots of the characteristic equation of the system. The characteristic equation is a polynomial equation that relates the input and output of the system. The poles of a system determine the stability of the system.
If a system has a pole in the right half of the complex plane, then the system is not BIBO stable. This is because the output of the system will grow unbounded for any bounded input.
If a system is causal, then it cannot have a pole in the right half of the complex plane. This is because the output of a causal system cannot precede the input.
Therefore, both statements 1 and 2 are true.