Array questions ask several sub-questions in one grid, so participants answer a set of related items in one go instead of working through the same question over and over. LimeSurvey offers five of them, and they differ by shape — what runs down the side, what runs across the top, and what participants fill in.
A No answer option is added automatically to the choice-based arrays when the question is not mandatory.
With Array (Point choice) you write the answer options yourself, so the scale is however long you need it. Older LimeSurvey versions had fixed variants for this — Array (5 point choice), Array (10 point choice), Array (Yes/No/Uncertain) and Array (Increase/Same/Decrease) — each hard-wired to one set of answers. Those are no longer offered: create the question as Array (Point choice) and type the answers you want. Surveys built on the old types keep working.
An array is a single question with several sub-questions inside it, all sharing one answer scale. A question group is a container that holds separate questions, usually shown as one page. If your items need different answer options, use separate questions in a group rather than an array.