Introduction:
An ADC (Analog-to-Digital Converter) is a device that converts analog signals into digital form. The successive approximation ADC is a type of ADC that uses a binary search algorithm to approximate the input analog voltage. It is widely used in various applications where high-resolution conversion is required.

Explanation:
The successive approximation ADC has a specific number of inputs that can be connected at a time. Let's analyze the options given in the question to determine the correct answer.

- Option 'A': 4 inputs connected at a time.
- Option 'B': 2 inputs connected at a time.
- Option 'C': 8 inputs connected at a time.
- Option 'D': 16 inputs connected at a time.

Successive Approximation ADC:
The successive approximation ADC has an input multiplexer that allows multiple inputs to be connected to the ADC. This multiplexer selects one input at a time for conversion. The selected input is then connected to a sample and hold circuit, which holds the voltage constant during the conversion process.

Number of Inputs:
The number of inputs that can be connected at a time depends on the design and configuration of the ADC. In the case of the successive approximation ADC, the number of inputs is determined by the number of channels in the input multiplexer.

Correct Answer:
According to the given options, the correct answer is option 'C', which states that 8 inputs can be connected at a time to an ADC that is integrated with successive approximation.

Conclusion:
The successive approximation ADC allows multiple inputs to be connected at a time through an input multiplexer. The correct answer to the question is option 'C', which states that 8 inputs can be connected at a time to an ADC integrated with successive approximation.