__________________ is the conversion of computer data from one format to another.

The process of changing computer data from one format into another format is called data conversion.

Data conversion happens whenever information stored in one representation needs to be usable in a different system or program, for example converting a file saved in one word-processor format into a different file format, or converting data from one character encoding to another so a different system can read it correctly.

Data transmission and data transfer both describe moving data from one location or device to another, they do not necessarily involve changing its format, and "data implementation" is not a recognised term for changing data format, so neither of these correctly matches the description in the question.

Exam tip: keep "conversion" (changing format) and "transmission or transfer" (moving location) as two separate ideas, a question describing a change in format is always pointing to conversion.