Sentences of a paragraph are given below in jumbled order. Arrange the sentences in the correct order to form a meaningful and coherent paragraph.

A. Once upon a time, a traditional classroom consisted of 30-40 students sitting and listening to teacher lectures for a couple of hours. 

B. Classrooms are becoming more technologically advanced through the addition of digital educational tools such as laptops, printers and LCD projectors. 

C. Nowadays, the typical learning process and the structure of classrooms are gradually shifting.

D. Recently, over 12,000 schools in 560 districts in India have implemented smart classes.