here we need to understand some things in the diagram :
1) from A packet is originated with Hop Count 3 towards E . (shown in 1st level of the tree). A to B and C.
2) B and C receives packet from A hence they can't send packets again to A . B will send to C and D. and C will send to B and D.( shown in second level of the tree) . Hop Count decreases to 2.
3) similarly as above in the third level, C will send packets to A and D but not B as the packet is just received from B. D to C and E. similarly for all other nodes in this level. Hop Count decreases to 1.
4) in the last level all the nodes received packets from previous level nodes and decrement the Hop Count by 1 . it becomes zero, hence cannot be transmitted anymore.
So now u can count all the packets as circled nodes in this diagram, which is equal to 14.