Is the answer and explaination given correct ?
@sushant my answer is correct or gf's, @kaushik the video explaination says the answer is 2. here is the link : https://d2h3n22tzbcxdg.cloudfront.net/172276/Videos/CS-ID-172276_R12.mp4
Sorry, Answer is wrong but explanation is correct. Rank doesnt change by pre/post-multiplication by non-singular matrix.
X->YZ , Y->XZ , ...