If data is an ndarray, index must be the same length as data.

The correct answer is False.

An ndarray is a multi-dimensional array in NumPy. The index of an ndarray is a tuple of integers that specifies the location of an element in the array. The length of the index must be equal to the number of dimensions in the array.

For example, if data is a 2D array, then the index must be a tuple of two integers. If data is a 3D array, then the index must be a tuple of three integers.

Therefore, it is not always true that the index must be the same length as data.