Hey @Hraday,
I just submitted your code for all the exercises and it is passing the grader and getting a complete score. I guess you have unintentionally changed something which you were not supposed to change. Please follow the instructions here to get a new notebook, and paste your solutions in that, and then try to submit your code. Hopefully, this will help you.
P.S. - For future references, posting solution code publicly is strictly against the community guidelines.
Cheers,
Elemento