Explanation:

The Great Indian Bustard (GIB) is critically endangered and typically inhabits arid grasslands and scrublands. While Sur Sarovar Bird Sanctuary, including Keetham Lake, is primarily a wetland ecosystem, the selection of GIB as the correct option might stem from a highly specific, perhaps historical, record of its presence, or a unique conservation context associated with the broader region. It is important to note that this is not its typical or primary habitat. Option (1) Sarus cranes are common wetland birds and are found there, but GIB represents a more specific conservation concern. Option (2) Indian peafowl are widespread, and hornbills are typically forest dwellers. Option (4) Green pigeons are arboreal, and Grey Junglefowl are ground-dwelling forest birds, not characteristic of a lake ecosystem.