First, if you want to become an IAS, so why are you going for engineering??? Koi sammand nehein hein. Just waste of time. Kahan IAS ka preparation aur Kahan engineering. Ekbr engineering Mein ghus gaye toh IAS ko bhul jaoge. Issey Accha hein, koi easy subject leke bsc karlo, aur side Mein IAS ki preparation karte raho. IAS k liye toh sirf graduation e chahiye. Toh Phir Kyun engineering Mein akein tym waste karna...
& according to your question aslo, computer science engineering is best,, IT mat lo