Parents B1/B2 Visa got Denied

[VB-100]

I applied for my parents b1/b2 visa. I am an Australian citizen married to US citizen living in Australia. During the application, I filled myself as a sponsor. I have been married for 7 years and my parents' have not met my father in law yet. The travel purpose of that application was to meet my father in law and attend my sister in laws' wedding (15 day trip).  We attached all my financial documents. I have also had all the hotels booking attached. They got denied on the basis of 214 (b) not showing strong ties to home country. I still don't understand on what basis they denied the visa age wise, my father is 70 years old and mother 66 years old. They have travelled previously 4 times to Australia and always came back within a reasonable time. 

 

Questions asked:

1. Why are you going to US? To meet my sons' father in law and attend his sister in law's wedding
2. Where do they live? California
3. For How long are you going? 2 weeks
4. What does your sons' father in law do? He is a builder
5. Where are your kids are living? They are well settled in Australia and citizen of Australia.
6. Have you ever travelled outside India? Yes 4 times in past 4 years.
7. What do you do for work? I have a transportation business (Single proprietorship)
8. How much do you earn? Rs.50000 monthly
9. Why are you going to colorado? We don't know anything about colorado, our kids booked trip. 

 

I am confused why the hell they would ask if they are going to colorado when they are not going. The only place we put was California.

 

Documents we attached in the application:

• My Salary slips from Australia
• My 3 Years Tax returns
• My 3 Months Bank Statement
• A combined invitation letter from my wife (US citizen)
• My Fathers' 3 Years tax returns
• My Fathers' house papers
• My Father's savings and current account statement (Total 10Lac)
• Invitation from My sister in law to attend her wedding
• Hotel bookings for my parents
• Passport copies of my wife, Sister in law and my Australian passport

 

We are applying b2 visa this week with self funded. Any help would be appreciated.