Which of the following statements with regard to the Indian Peninsular Plateau is/are correct?

1. Roughly triangular in shape with its base coinciding with the southern edge of the great plain of North India.

2. It is a highly stable block composed mostly of the Archaean gneisses and schists.

3. The trough of the Narmada and Tapti is interposed between the Vindhyan and the Satpura ranges.

Select the correct answer using the codes given below.