2 different years will have the same calendar if the total number of odd days from one year to the other is 7 or multiple of 7.
So from 1990, if we go forward, odd days in 1991–1, 1992 – 2, 1993 – 1, 1994 – 1, 1995 – 1, 1996 – 2, 1997 – 1, 1998 – 1, 1999 – 1, 2000 – 2, 2001 – 1. Total number of odd days up to 2001= 1 + 2 + 1 + 1 + 1 + 2 + 1 + 1 + 1 + 2 + 1 = 14.
Hence 2001 will have same calendar as 1990.