@MDivakarPal ur answer is wrong
c is correct option
Choices of numbers = 10
Choices of uppercase letters = 26
Choices of lowercase letters = 26
There are three characters in a password, one from each category.
If the positions were fixed, number of passwords possible = 10 * 26 * 26 = 6760
Accounting for changes in position, no of passwords possible = 3! * 6760 = 40560