Which option best describes a jagged array?

A jagged array is best described as an array whose elements are arrays of varying sizes. Unlike a rectangular array, where each row has the same number of columns, a jagged array allows each row to have a different number of columns, making it flexible in terms of the number of elements that can be stored. This structure is particularly useful when dealing with data that does not naturally fit into a uniform grid, such as lists of varying lengths or records that have different numbers of properties among their instances.

The other options do not accurately capture the nature of a jagged array. While fixed-sized elements and uniform sizes pertain to traditional arrays, which maintain a consistent structure, jagged arrays intentionally break away from this uniformity. Furthermore, an array that automatically resizes pertains to dynamic arrays or array lists rather than jagged arrays, which are defined by their varying lengths rather than their resizing capabilities.