What does the term “hard yakka” refer to?

Here is the question :

WHAT DOES THE TERM “HARD YAKKA” REFER TO?

Here is the option for the question :

Hard work
Hard shell
Hard liquor
Hard hat

The Answer:

And, the answer for the the question is :

Hard work

Explanation:

[STC0011262]. ‘Yakka’ originates from the Yagara Aboriginal Australian word ‘yaga’. Australians today use the term to describe laborious effort, however the expression ‘all yak and no yakka’ refers to someone who is all talk and no action.