Which of the following statements is/are correct?

a. The sedimentary rocks, which were accumulated in the geosyncline known as the Tethys, were folded to form the mountain system of western Asia and Himalayas. b. The Himalayan uplift out of the Tethys sea and subsidence of the northern flank of the peninsular plateau resulted in the formation of the large basin that became the northern plains. c. Geologically, the peninsular plateau of the Indian subcontinent is supposed to be one of the most stable land blocks.