Final answer:
The length of an array in Java is determined by the number of elements in the array. Once an array is created using the 'new' keyword, its length is fixed and cannot be changed at runtime.
Step-by-step explanation:
In Java, the length of an array is determined by the number of elements in the array. Therefore, the correct option is: d) It is determined by the number of elements in the array. In Java, when an array is created using the new keyword, the size of the array is specified, and it cannot be changed at runtime. The length of the array is a fixed property defined during its creation. Accessing the length of an array is done using the `length` attribute, for example, array.length. This attribute provides the number of elements in the array, allowing developers to iterate through the array or perform operations based on its size.