Refer to the exhibit. P1 and P3 cannot establish an LDP session between them. Which reason for this issue is true?
A. Mismatched LDP discovery hold timers are between P1 and P3.
B. P1 is not configured to send LDP discovery packets to P3.
C. P3 cannot discover P1 because P3 has a route to each P1.
D. The LDP transport source address used on P3 is incorrectly configured.