Which of the following are among the million-plus cities in India on the basis of data of the Census, 2001? 1. Ludhiana 2. Kochi 3. Surat 4. Nagpur Select the correct answer using the code given below:

1. (a)1, 2 and 3 only
2. (b)2, 3 and 4 only
3. (c)1 and 4 only
4. (d)1, 2, 3 and 4