Final answer:
The domain words 'electric guitar,' 'Frying Pan,' 'the Log,' 'steel guitar,' and 'acoustic guitar' can be best categorized under D. 'Guitar Varieties,' as they represent different types of guitars.
Step-by-step explanation:
The domain words 'electric guitar,' 'Frying Pan,' 'the Log,' 'steel guitar,' and 'acoustic guitar' are best grouped under the topic 'Guitar Varieties.' This categorization reflects the different types of guitars and their unique qualities. An electric guitar relies on electromagnetic pickups and amplification, the 'Frying Pan' refers to one of the first electric lap steel guitars, 'the Log' is a prototype for solid-body electric guitars, a steel guitar is known for its use in country and Hawaiian music, and an acoustic guitar produces sound acoustically through the vibration of the strings and resonance of the body.