Choose the best option to fill in the blank with the correct phrase given below:-

Anokhi worked tirelessly _____ her children's future, ensuring they had every opportunity.

for the sake of

The correct answer is Option (4) → for the sake of

For the sake of (Idiom/Phrase): Means in order to achieve or preserve something; out of concern or desire for. This fits the context, as Anokhi's tireless work was done specifically to benefit or preserve the quality of her children's future.

Other Options: 

• On behalf of (Phrase): Means as a representative of someone, or in their place (e.g., She accepted the award on behalf of her team).

• By way of (Phrase): Means via, or as a method of (e.g., She introduced herself by way of an anecdote).

• In case of (Phrase): Means in the event of (e.g., In case of fire, use the stairs).