Networking Fundamentals — Question 48

Which subnet mask is valid?

Answer options

• A. 255.255.255.240
• B. 255.255.255.228
• C. 255.255.255.164
• D. 255.255.255.245

Correct answer: A

Explanation

The correct answer is A (255.255.255.240) because it is a standard subnet mask that allows for 16 usable addresses. The other options (B, C, and D) do not represent valid subnet masks, as they do not align with the subnetting rules that require masks to have consecutive '1's followed by consecutive '0's.