Re: para completion -- doubt
option A) is cleary out of context.
option B) may be considered, so we keep it.
option C) and D) give an opposite idea than what should come after the line " we should not make these mistakes.. ". these give an idea that we should do these mistakes.
option E) may also be considered.
now, since there is a problem in two given options, we advice you to leave this question unmarked in the exam. marking this question , you may acquire a negative mark.