Official Solution: The process of image processing is the method by which image signal is converted to physical image by using photographic software.A. The process of Image processing is the method by which image signal is converted to physical image
B. The process of image processing is the way that image signal is converted to physical image
C. Image processing is the process by which image signal is converted to physical image
D. Image processing occurs when image signal is converted to physical image
E. Image processing, the process by which image signal is converted to physical image
Choice (A): The use of both process and method makes a redundant repetition. Both refer to the same process and only one reference should be sufficient. Incorrect.
Choice (B): Same explanation as above, the only difference is the use of "the way" in place of "the method". Incorrect.
Choice (C): Correct: this choice uses only one reference to the process and "process by which" is idiomatic an concise.
Choice (D): This choice expresses that image processing occurs as a result of converting. But the actual meaning expresses that the process is the converting into physical image. Incorrect.
Choice (E): This choice lacks a verb and is a fragment. Incorrect.
Answer: C