Question about CS Minor and Branch Change at IITK

Hi! My cousin is likely joining IIT Kanpur in Civil this year. I had a couple of questions

1.Can Civil students pursue a CS minor? Is selection mainly based on CPI?

2. How difficult is it to get a CS minor?

3.Is branch change after first year still possible, and realistically how hard is it to switch out of Civil later?

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Would appreciate input from current students or alumni. Thanks!