Explanation:

Correct Answer is (c).In this sentence, the predicate part followed by "..his knowledge and ..." has to be a noun phrase and hence the adjective 'attentive' must be replaced with the noun 'attention'. 
And at the same time, it's more appropriate and common to use 'to' after 'attention' and not 'of'. The correct formation, hence, will be- The incident has clearly highlighted his knowledge and attention to detail. Hence, the option C is correct.