A. ICMP echo requests are sent to 172.19.102.2 in five-millisecond intervals.
B. ICMP echo requests are sent to 172.19.102.2 until five packets are dropped.
C. ICMP echo requests are sent to 172.19.102.2 five times.
D. ICMP echo requests are sent continuously to 172.19.102.2 for five seconds.
参考答案：C
