Final answer:
In a Java two-dimensional array declared as double[4][5], x.length is 4, representing the number of rows, and x[2].length is 5, indicating the number of columns in the third row. The correct answer is option b. 4 and 5.
Step-by-step explanation:
When dealing with arrays in Java, a double[4][5] represents a two-dimensional array, also known as a matrix. The array consists of 4 rows and 5 columns, which means we have 4 arrays of doubles, each containing 5 elements.
The .length property in Java returns the number of elements in the specified array dimension. For the array x declared as new double[4][5], x.length represents the first dimension's length, which corresponds to the number of rows. In this case, x.length would return 4. On the other hand, x[2].length queries the length of the third row (since array indexing starts at 0), which reveals the number of columns. Since each row has the same number of columns, x[2].length would return 5. Therefore, for the array x, x.length is 4 and x[2].length is 5.
The correct answer to the question, "What are x.length and x[2].length?" is option b. 4 and 5.