Consider three approach to implement file system$\mathrm{.}1.$ The directory is an array with fixed$-$length entries. Each entry contains a valid file name or is free$\mathrm{.}2.$ The directory is an array with variable$-$length entries. Each entry contains a length field and either a valid file name or is free$\mathrm{.}3.$ The directory is an array with variable$-$length entries. Each entry contains a valid file name, followed by a possibly empty hole. Each entry also contains two pointers, one pointing to the end of the entry and the second to the end of the file name.When the length of a file name decreases, the file entry will always have to move to a different position with approach$010203$ None