Complete the proverb, in the following question:
When _____________ is bliss, it is ______ to be wise.
When ignorance is bliss, it is folly to be wise.
Where 'ignorance' is bliss, ‘it is 'folly' to be wise is the correct proverb that means, if knowledge brings unhappiness it is better to be ignorant. Therefore 'ignorance and folly' is the correct option.