The anti-corruption commission in Bangladesh launched an extensive investigation after it was revealed that senior bureaucrats had been systematically siphoning ________ funds from education budgets, depriving schools of much-needed supplies and improvements.

• শূন্যস্থানে সঠিক উত্তর হবে - off.
- Complete sentence: The anti-corruption commission in Bangladesh launched an extensive investigation after it was revealed that senior bureaucrats had been systematically siphoning off funds from education budgets, depriving schools of much-needed supplies and improvements.

• siphon something off (phrasal verb with siphon verb)
English Meaning: to dishonestly take money from an organization or other supply, and use it for a purpose for which it was not intended.
Bangla Meaning: অসৎ উপায়ে অর্থ উপার্জন।

Source:
1. Cambridge Dictionary.
2. Accessible Dictionary by Bangla Academy.