Region of Convergence of a Causal LTI System
Understanding the concept of Region of Convergence (ROC) in the context of a causal Linear Time-Invariant (LTI) system is crucial in signal processing and system analysis. The ROC indicates the range of values for which the system's output converges, given an input signal.

Definition of a Causal LTI System
A causal LTI system is one in which the output at any given time depends only on the input at the current and past times, not on future inputs. This implies that the system cannot anticipate future inputs when generating the output.

Region of Convergence (ROC) for a Causal LTI System
For a causal LTI system, the ROC is defined as the region in the complex s-plane for which the system's impulse response is absolutely summable. In other words, the system is stable and the output converges for values of s within the ROC.

Correct Answer: B) Is the right-half of s-plane
In the case of a causal LTI system, the ROC is typically the region to the right of the rightmost pole of the system. This is because for the system to be stable, the poles must lie on the left-hand side of the complex plane. Therefore, the ROC for a causal LTI system is the right-half of the s-plane.

Explanation
The right-half of the s-plane includes all values of s with positive real parts. This region ensures that the system is stable and that the output converges for a causal LTI system. By contrast, the left-half of the s-plane would not be a valid ROC for a causal system, as it would lead to unstable behavior.
In conclusion, the Region of Convergence for a causal LTI system is the right-half of the s-plane, ensuring stability and convergence of the system's output. Understanding the ROC is essential for analyzing and designing systems in signal processing and control theory.