Read this and answer the question. If the question is unanswerable, say "unanswerable".

When granting assent by commission, the sovereign authorises three or more (normally five) lords who are Privy Counsellors to grant assent in his or her name. The Lords Commissioners, as the monarch's representatives are known, wear scarlet parliamentary robes and sit on a bench between the throne and the Woolsack. The Lords Reading Clerk reads the commission aloud; the senior commissioner then states, "My Lords, in obedience to Her Majesty's Commands, and by virtue of the Commission which has been now read, We do declare and notify to you, the Lords Spiritual and Temporal and Commons in Parliament assembled, that Her Majesty has given Her Royal Assent to the several Acts in the Commission mentioned."

Who wears blue parliamentary robes?
unanswerable