Step 1: Identify the national waterways declared by the government.
The government of India has declared several waterways as National Waterways.
The Ganga Waterway between Haldia and Allahabad (National Waterway 1) and the Brahmaputra Waterway between Sadiya and Dhubri (National Waterway 2) are major national waterways.
The Western Coastal Canal in Kerala (National Waterway 3) is also declared as a National Waterway.
Step 2: Check the validity of each option.
Option (A):
Incorrect, as both the Ganga and Brahmaputra waterways are valid.
Option (B):
Incorrect, as both the Ganga and Brahmaputra waterways are valid.
Option (C):
Correct, as the Ganga and Brahmaputra waterways are valid.
Option (D):
Correct, as all listed waterways are national waterways.