What are the effects of discharging excess heat from electrical power stations into rivers and lakes? (i) The biological oxygen demand value of the water decreases (ii) Instant death of certain organism (iii) The population of algae increases (iv) The concentration of dissolved oxygen increases

• A.  Only (i) and (ii)
• B.                         Only (ii) and (iii)
• C.                         Only (i), (ii) and (iii)
• D.                         Only (i),(ii) and (iv)