Challenges to and restoration of the congress system

Which of these statements about the 1967 elections is/are correct?
(a) Congress won the Lok Sabha elections but lost the Assembly
elections in many states.
(b) Congress lost both Lok Sabha and Assembly elections.
(c) Congress lost majority in the Lok Sabha but formed a coalition
government with the support of some other parties.
(d) Congress retained power at the Centre with an increased majority.