NEET Biology question

Thinking-type: A student notices that a water body near an industrial area has an extremely low dissolved oxygen level and supports very little aquatic life, despite receiving regular inflow of treated sewage effluent. The most likely explanation is that the

• (A)effluent still carries a relatively high BOD, so resident microbes continue consuming dissolved oxygen, depleting it for aquatic organismsCorrect
• (B)effluent is completely free of any organic matter
• (C)water body has excess dissolved oxygen that harms aquatic life
• (D)sewage treatment process added more oxygen than needed