Question about Loopback Testing

Question

My machine's local host IP address is 192.168.0.15, and I do loopback test  on Windows 10.
I use two ping commands as follows, but both are failed (responded by saying "PING: Transmit failed
General failure")
C:\> ping 192.168.0.15 -S 127.0.0.1
C:\> ping 127.0.0.1 -S 192.168.0.15
Can someone help explain that to me?
There are no problems if I use the ping commands
C:\> ping 192.168.0.15   AND  C:\>ping 127.0.0.1

Comments

What is the use of "-S"?

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-S <srcaddr> means to designate the source IP address of this icmp datagram.