Which subnet mask is equivalent to slash notation `/24`?

### Why this is right A `/24` prefix has 24 leading network bits set to one, followed by 8 host bits set to zero. In dotted-decimal form, each full group of eight ones is 255 and the final group of eight zeroes is 0, giving `255.255.255.0`. ### The concept A subnet mask is another way to express which bits of an IPv4 address identify the network. The mask `255.255.255.0` has three full octets of ones, or 24 network bits. It leaves the final octet available to vary within the subnet. A mask does not itself give the address of a device; it is interpreted together with that device's IP address. ### The other options - **A. 255.255.255.255**: This is the mask for `/32`, where all 32 bits identify one address. It is tempting because it is another listed mask, but it does not represent `/24`. - **C. 0.0.0.0**: This corresponds to `/0`, with no network bits fixed. It is not a `/24` mask. - **D. 255.255.0.0**: This has 16 leading one bits and corresponds to `/16`, not `/24`. ### Terms - **Subnet mask**: A value showing which address bits identify the network and which can vary. - **Octet**: An eight-bit group in an IPv4 address or mask. - **IPv4**: Internet Protocol version 4, a 32-bit addressing system. ### Remember Each `255` in a subnet mask represents eight network bits; `255.255.255.0` therefore means `/24`.