Hooghly Matlah is a:

Correct option is A

Correct Answer: (a) Positive estuary
Explanation:
→ Hooghly-Matlah (the estuarine region of the Hooghly River) is classified as a positive (classical) estuary, where freshwater inflow and tidal mixing create a salinity gradient with lower salinity upstream and higher near the sea.
Information Booster:
→ Positive estuaries typically show estuarine circulation (landward flow at surface, seaward at depth) and support diverse fisheries.
Additional Information (Other Options):
(b) Negative estuaries occur in arid regions; (c) Mixed estuary indicates intermediate mixing regime; (d) Backwaters are lagoon/lagoonal systems.