The correct answer is C. 192.168.1.10. A valid IPv4 address is written in dotted-decimal notation, using four decimal numbers separated by periods. Option A is formatted like a MAC address, not an IP address. Option B has no dotted-decimal separation. Option D uses colons, which is not the standard IPv4 dotted-decimal format.
Exact Extract/Reference: The CompTIA Tech+ Study Guide states that an IP address is "typically written in dotted-decimal notation," such as 192.168.10.55, and explains that each number represents an octet. The guide also distinguishes IP addresses from MAC addresses, noting that an IP address is logical and a MAC address is physical.