The statement given in option (a) is correct.
Explanation
The 1967 elections were a big jolt for the Congress. Although the party won the Lok Sabha and formed government at the centre, it lost in as many nine states. This marked the end of one-party dominant system. This was the first time that any non-Congress party had secured a majority of its own in the state of Tamil Nadu. In the other eight states, coalition governments consisting of different non-Congress parties were formed.