Best spark plug to use in a Elan Skidoo?

[skidoodude]

I have a 1980s Elan skidoo with a 247 single cylinder Rotax motor in it

what spark plug should i be using in it?

Any help sure would be appreciated..

Thanks Skidoodude

[SKIBORG]

A7 A8 or ab-6 NGK
d-14 champions