Which HTML pattern attribute would validate an IPv4 address?

The chosen answer is correct because the pattern attribute in HTML is used to specify a regular expression that defines the allowable format for the input data. The pattern provided in the second option, which is \d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}, accurately fits the required structure of an IPv4 address.

An IPv4 address consists of four sets of numbers, separated by periods, where each number can be from 0 to 255. In regex, \d matches any digit (0-9), while {1,3} indicates that the preceding element (a digit in this case) must occur between one and three times, thus allowing for numbers like "1", "100", or "255". The use of \. specifies that the period is a literal character separating the octets of the IP address.

Combining these components, the pattern recognizes sequences like "192.168.1.1" or "10.0.0.255", making it suitable for validating IPv4 addresses in an input field.

Other patterns presented do not fit the IPv4 address format, either by validating different types of input or by having incorrect