Should I study lateral B.Tech (which will be second bachelor's degree for me) or MCA in India for studying MS in US ?

I have already completed B.Sc. in India with PCM subjects. Now I want to get into CS. For this I have two choices. I can either take lateral admission in B. Tech (CS) 3rd semester (which some universities in India offer to Bsc. graduates) or I can do MCA. Which one will be better as I plan to do MS in US? Will I become eligible for MS after post B.Sc. lateral B. Tech. (which will be 3 years in duration) ? Also, if I do MCA, will I be questioned for duplicating Master’s degree when I’ll apply for MS ? Do you personally know anyone who has done MS from a US university after lateral B. Tech. or MCA ?

Well, if you can afford financially to do Bachelors for the remaining courses to get the degree in US, I do not see any reason you should pursue that path. Yes, it can get tricky, if you get another Masters degree from India and again try to do the same thing in US at Visa stamping. Also, why do you want to study masters second time. Check with schools, what are your best options to do transition. You may write to few schools admissions and get their response.