Help me in solving MATHMCQ5 problem

My issue

I don’t get the solution explanation please help

Learning course: Basic Math using C++
Problem Link: CodeChef: Practical coding for everyone

here you have to select multipe correct answer i.e
option 1 is wrong because of it left the 10000.
option 2 is right because it contains smallest 5 digit number 10000,
option 3 is wrong beacuse it contains greater then 5 digit number.
option 4 is right because it contains less than 99999 largest 5 digit no.