Let us analyze what the author intends to convey through the given sentence.
'Although these injuries are not fatal,......'.
The author acknowledges that the injuries are not fatal. By using the word 'although', the author conveys that he expects something to be done but that is not the case. The part that completes the sentence should capture this point.
'they are not ranked among top causes of death'. Had the option been 'they are ranked ...', we could have used this option to fill the blank. The given option cannot be used since it contradicts the term 'although' used in the first part of the sentence.
'they do not get reported'. There is nothing peculiar about minor injuries going unreported. This option will also make the usage of although in the first part of the sentence incorrect and hence, option D can be eliminated as well.
'there is no proof of the same'. This statement can be used to fill the blank. Let us check the other option and choose the most appropriate one between the two.
'they are certainly incapacitating and tragic'. This option aptly concludes by continuing the chain of thought. Though the injuries are not life threatening, they are certainly crippling. Therefore, option B is deemed better than option C and hence, option C is the right answer.