I can answer C).

First, it is important to be clear on what we mean by a nobleman. If we mean someone who has a title equivalent to a member of the House of Lords in England - Lords, margrafs, earls, counts, dukes, grafs, barons etc., then we are talking about the very highest rank of the aristocracy. Below them were title knights, and then untitled 'gentleman' - at least in England.

Assuming that by 'noble' we do mean 'graf/earl/coung etc.'....

The average nobleman would own full plate armour, probably of a very high quality, compared with his social inferiors among knights, 'esquires' and 'gentlemen.' In much of Europe, he would be equipped (Most of the time) as a heavy cavalryman, wearing full plate armour and riding an armoured warhorse. The armour of this period was the most complete and protective in history - much of what survives was heat treated for extra hardness, and armourers from 1420 on had become very good at enclosing men at arms entirely in plate armour - a nobleman could afford the best, and if he picked a good armourer (from Innsbruck or Augsburg or Landshut, say), he would get what he paid for. Oddly enough Italian armour of this period stops being heat treated, though the basic steel remains sound. Fine quality armour (like that of a noble) would be decorated with etching and gilding. Some armours are decorated with paralell fluting (19th century collectors called these 'maximialian' armours) while most have fairly smooth surfaces. This armour shows the armour of a powerful nobleman, and is displayed with the horse armour of another noble. Note that not all of the original gilding survives - originally all of those darker areas would be covered in gold.

Heavy cavalry was equipped with a rather long lance that swelled above and below the grip, and was supported by a lance rest when men at arms charge. The heavy cavalryman suffers a number of defeats in this period, such as at Pavia, and lighter types of cavalry become more common (in no small part because of economic reasons) but aristocratic warriors still fight as men at arms through 1540 and beyond.

In England nobles would still sometimes fight on foot, with the rest of the gentlemen at arms - for instance at the Battle of Flodden. The a number of Scottish nobles, including the king, also fought with their own infantry at Flodden, probably dismounted. Dismounted men at arms would be armed with a variety of polearms, most commonly the pollaxe - a 4'-6' shaft with some combination of axe head, hammer head and spikes. They would also be equipped with swords.