Which of the following statements about RIP is true?

RIP, which stands for Routing Information Protocol, primarily operates as a classful routing protocol. This means that it does not support variable-length subnet masking (VLSM) and treats all subnets within a network as belonging to a single larger classful network. Consequently, it does not allow routers to share routing information about routes that have different subnet masks within the same major network. This characteristic significantly limits its applicability in modern networking environments where subnetting is a common practice. Thus, option D accurately reflects a key limitation of RIP.

Other options describe attributes or functionalities of RIP that are either mischaracterized or incorrect. For instance, RIP does have mechanisms for infinite loop prevention, such as split horizon and route poisoning, additionally managing route stabilization through hold-down timers. However, it does not rely solely on holding down routes for loop prevention, which makes the first statement misleading. The phrase about dynamic adjustment to complex network changes does not accurately represent RIP's functionality, as it is relatively slow to converge and not well-suited for quickly changing topologies. Lastly, the maximum hop count for RIP is set at 15, making it unable to support any route that requires more than 15 hops to reach, instead of the incorrect value of 20 presented