Question

The Grand Canal was built to connect the 1.
Yellow Sea and the East China Sea. 2.the Yangtze River and the East China Sea. the 3. Huang He River and the Yangtze River. the 4.Huang He River and the Yellow Sea.

Answer 1

The Grand Canal is the oldest and the longest canal in the world.

The canal is located in China and it connects (3) the Huang He River (Yellow River) and the Yangtze River.

The canal extends much beyond the two rivers. The canal begins in Beijing (North) and ends in Hangzhou (South).

Answer 2

The grand Canal of China, one of the world heritage sites was built to connect the Huang He River and the Yangtze River.  

The grand Canal is the oldest and longest canal in the world. It starts from Beijing and passes across Tianjin, Shandong, Hebei, Jiangsu and Zhejiang and reaches Hangzhou city. The canal links the Huang He river which is formally known as the Yellow River and Yangtze river.

Hence the correct answer for your question option (3).