Which statement about RIPv1 and RIPv2 is true?

• A. RIPv1 carries masks in updates; RIPv2 omits them.
• B. RIPv1 is classful (no masks in updates); RIPv2 is classless and supports authentication (e.g., MD5).
• C. RIPv1 uses MD5 authentication; RIPv2 uses no authentication.
• D. RIPv1 is classful (no masks in updates); RIPv2 is classless and supports authentication.

Answer: (B)

RIPv1 and RIPv2 differ in how they handle subnet information and security. RIPv1 is classful, meaning it does not carry subnet masks in its updates and relies on the class of the IP address to determine the mask. This limits its ability to support VLSM or CIDR. RIPv2 is classless, so it includes subnet mask information in updates, enabling variable-length subnet masks and more flexible addressing. It also adds optional authentication, such as MD5, to protect routing updates. This combination—RIPv1’s lack of masks and RIPv2’s classless updates plus authentication—matches the statement and is why it’s the correct description.