Having a bit of an issue with this practice question. The books says the answer is d. 9 seconds, but I maintain that the answer is c. 10 seconds. I don't know if this is one of those semantics questions where the thought process is that the router knows that a neighbor is down at 9 seconds but doesn't declare it to be down until 10 seconds has elapsed - or maybe it's just another wrong answer in the FLG which there seem to be plenty of.

Thoughts?
How long does a standby router take to detect the loss of the active router in HSRP with default timer values?
a. 15 seconds
b. 3 seconds
c. 10 seconds
d. 9 seconds
e <1 second