Energy Signal:
An energy signal, denoted by x(t) or x(n), is a signal whose total energy content is finite. It is characterized by the fact that the signal amplitude approaches zero as time goes to infinity.

Total Energy:
The total energy of a signal x(t) or x(n) is calculated by integrating the square of the signal amplitude over the entire time duration. Mathematically, the total energy E is given by:

E = ∫ |x(t)|² dt or E = ∑ |x(n)|²

where |x(t)| or |x(n)| represents the magnitude of the signal at each time instant.

Explanation:
The question asks whether the total energy content of an energy signal is a finite quantity, infinite, zero, or none of the mentioned options. The correct answer is option 'A', which states that the total energy is a finite quantity.

Reasoning:
To understand why the total energy of an energy signal is a finite quantity, we need to consider the definition and properties of energy signals.

1. Definition of Energy Signal:
An energy signal is a signal whose total energy is finite. This means that the signal has a finite amount of energy distributed over its entire duration.

2. Signal Amplitude:
In an energy signal, the amplitude approaches zero as time goes to infinity. This implies that the signal does not have infinitely large values, but rather decreases in magnitude over time.

3. Total Energy Calculation:
The total energy of a signal is calculated by integrating the square of the signal amplitude over the entire time duration. This integration or summation process results in a finite value since the signal amplitude is finite and approaches zero as time goes to infinity.

4. Finite Energy:
Since an energy signal has a finite amplitude and the total energy is calculated by integrating or summing the square of the amplitude, the resulting value will always be finite. This is because the square of a finite value is always finite, and the integration or summation process over a finite duration does not yield an infinite result.

Therefore, the total energy content of an energy signal is always a finite quantity.