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The correct answer is B.

OBJ-3.1: The correct answer is \b172\.16\.1\.(25[0-5]|19[2-9]|2[0-4][0-9])\b. The \b delimiter indicates that we are looking for whole words for the complete string. To answer this question, you have to rely on your networking knowledge and what you learned back in Network+. First, you need to calculate what is the IP range for this subnet. Since this is a /26, it would have 64 IP addresses in the range. Since the IP provided was 172.16.1.224, the range would be 172.16.1.192 to 172.16.1.255. The correct answer allows all values of 200-249 through the use of the phrase 2[0-4][0-9]. The values of 250-255 are specified by 25[0-5]. The values of 192-199 are specified through the use of 19[2-9]. All other REGEX expressions either allow too much or too little of the available IP space to be effective and precise filters for the subnet given. If you had this on the exam, I would calculate the IP address range first (as we did in this explanation). Then, I would see which parts are static in the IP address (172.16.1. in this case). Three of our answer choices provide this, so we now know the large REGEX is the wrong answer. Next, we need to figure out how only to show the values of 192-255. As you look at the three options, you need to look for the differences only between the options and see which would allow for the addresses needed. All three options have the same two first terms in the last octet, which covers 200-255, so you need to determine how to represent the values of 192-199 best./span>

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