and you won a jackpot (let's say for the sake of argument, £10m), what would be the etiquette as regards the person who gifted you the winning ticket?

a) Keep it all for yourself, it was given as a ticket, you winning something was the aim of the gift
b) Even split to acknowledge the fact that without them buying the ticket, you'd have nothing
c) Some gift to them, as a thank you
d) Give it all to them