i just used option elimination method in this question.
for example lets see point 4. we can clearly see that it is false beacuse smallest string can be 0.
now clearly option A and C will be eliminated because it doesn't contain point 4.
now we can easily check using transition table of dfa that the given dfa is not minimal.
so answer will be D
P.S These will work faster as in point 2 we may have to use ardent method i.e state elimination method for finding regular expression and that will be time consuming