An organization is granted a block of ip addresses with the starting address: 156.78.51.0/22. They want to create 5 subnets with the following number of addresses.

Subnet 1: 512 addresses

Subnet 2: 256 addresses

Subnet 3: 128 addresses

Subnet 4: 128 addresses

What should be the prefix of each subnet?

Subnet 1: /

Subnet2: /

Subnet 3: /

Subnet4: /