The correct option is B b
The option that has an error, is the correct option.
Option B: The error lies in part (b): 'a large number of hoarded sugar'. 'Number' is the error.
We use the word 'number' for countable nouns: 'a large number of people gathered', 'increase the number of women in the company'.
The noun 'sugar' is uncountable, it is made of grains and cannot possibly be counted.
The correction is 'a large amount of hoarded sugar'. 'Amount' modifies uncountable nouns.
Hence option B is the correct option with the error.
The other parts (a) and (c) do not have any error in them. They are grammatically correct and are complete in meaning.
Hence options A and C are not the right answers.
Option D is incorrect because the sentence has an error (b).