What does it indicate if you are approximately 320 feet to the left of the runway centerline and 21 feet above the glide slope at 1,300 feet?

When you are approximately 320 feet to the left of the runway centerline and 21 feet above the glide slope at 1,300 feet, this situation indicates that you are misaligned with both the horizontal and vertical guidance provided by the localizer and glide slope.

Being 320 feet to the left of the runway centerline suggests that you are not aligned properly with the localizer, which provides lateral guidance to reach the runway. Thus, you are on the left side, indicating you are off course.

In addition, being 21 feet above the glide slope means that you are higher than the ideal vertical path that you should be following to land correctly. The glide slope provides the necessary guidance for the descent angle when approaching the runway. Being above this path indicates that your approach needs correction to descend appropriately.

Taking both of these positional discrepancies into account, you are not only off to the left but also indicating a descent that is lower than required, which corresponds to being low in relation to where the glide slope indicates you should be. So, the situation accurately describes being both low and to the left of the localizer, which aligns with the provided answer.