Is it faster to get 80 attack from 79 by:

 

 

 

Killing Yaks

 

Going Apes at Ape Toll

 

Killing Ankous

 

Fire Giants

pest control is faster but ankous should do if you got a whip.

Slayer with a black mask would prbably be the fastest depending on your tasks.

 

 

 

but from that list, I'd say probably yaks.

i'd say Monkey>ankou>yaks.

 

 

 

ankou i put second assuming you have a salve (e), which gives a better bonus than black mask on a slayer task. Monkeys are fastest because you can keep piety on and wear the best attack bonus gear possible. with ankou you'd need some kind of defense plus slower exp while guthaning.