What equipment is optional for an A Class boat when racing?

This question is especially relevant to the Q&A concerning whether the boat may weigh less than the certified weight (less the tolerance).

Class Rule C.4.2 states that the boat shall sail with the hull, hull appendages, ballast, mast spar and main boom spar relating to the certificate. CR C.8.3 states the mainsail shall be set when racing. C.9.2 states rc equipment, if temporarily removed,  shall be replaced by items of similar weight in the same position. C.9.3 states the owner's flag is mandatory. CR F.1 states the rig shall consist of no more than one mast, one headsail luff spar, one main boom, one headsail boom, standing rigging, running rigging, wind indicators and owner's flag. CR G.1 states the sail plan shall consist of one mainsail and, optionally, one headsail.

From the above it is clear that the mandatory equipment comprises:

• hull
• hull appendages
• ballast
• mast spar
• main boom spar
• rc equipment of similar weight and position
• mainsail

And the remaining equipment is optional comprising:

• headsail luff spar
• headsail boom
• standing rigging
• running rigging
• wind indicators
• replacement of rc equipment of similar weight and position
• headsail