13. A signal is measured at two different points. The power is P1 at the first point and P2 at the second point. The decibel loss from the first point to the second point is -3 dB. This means a) c) P2 is zero P2 is 3 times of P1 b) d) P2 equals to P1 P2 is half of P1 14. PCM (Pulse Code Modulation): which quantization level results in a more faithful reproduction of the signal? a) 4 c) 16 b) 8 d) 32 15. For the network in the following figure, there are four (4) routers, namely A, B, C, and D. The cost between any two routers can be different to result different shortest-path trees by using the Dijkstra's algorithm for router A. How many different shortest-path trees for router A are possible? a) 2 c) 6 b) 4 d) 8