When a file occupying seven clusters is erased and another file of 610 bytes is saved in one cluster, how is that cluster described?

The correct answer points to the concept of slack space, which refers to the unused space in a cluster after a file is saved. When a file that occupies seven clusters is erased, its data is no longer actively referenced by the file system, yet it may still physically exist on the disk until overwritten.

In this case, when a new file of 610 bytes is saved in one cluster, it does not fully utilize the entire cluster capacity. Consequently, the remaining space in that cluster (after accounting for the 610 bytes) constitutes slack space. The total size of a cluster is typically larger than the file size, and any leftover space is still a part of that cluster.

Because the prior file occupied seven clusters, the cluster now holding the 610-byte file could still contain remnants of the deleted file in the slack space, which is essentially leftover data not cleared when the prior file was erased. Therefore, the correct description includes not only the current data of 610 bytes but also the residual data from the previous file that remains in the slack space, thus constituting 31,390 bytes that reflect that leftover information.