Consider an 802.11 ad hoc wireless network, and assume that nine wireless nodes are arranged in a uniform grid as shown in the figure to the right. For example, r meters separate nodes 1 and 2. Assume that each node has the same signal coverage and a circular shape represents the coverage (e.g., if the signal coverage is r meters then nodes 1 and 2 can transmit to each other but nodes 1 and 5 cannot). Assume that node 1 transmitted an RTS to node 2, node 2 transmitted a CTS to node 1, and node 1 is currently transmitting a data packet to node 2. At this instant, which nodes are permitted to transmit an RTS?