The correct option is C c
The option that has an error, is the correct option.
Option C: The error lies in part (c): 'in meaningful way'.
The article 'a' is missing here; it should be 'in a meaningful way'.
The noun 'way' is a singular, countable noun and hence it cannot do without one. It requires an article 'a'. (the noun is non-specific, thus we use 'a'.)
So, option C is the correct option with the error.
The other parts (a) and (b) do not have any error in them. They are grammatically correct and are complete in meaning.
Hence options A and B are not the right answers.
Option D is incorrect because the sentence has an error (c).