In the book of Merit nation there is a question:

Which of the following statements about the process of digestion is incorrect?

a) It involves the breakdown of complex food substances into simple ones
b) It takes place inside special digestive structures
c) It takes place only in multicellular organisms
d) It helps in providing nutrition to the body

I think the answer is (c) as it also takes place in unicellular organisms and it is written in the solution booklet that digestion is not restricted to multicellular organisms and also takes place in unicellular organisms like Amoeba.  But, the answer is given as (b).

Please tell the write answer as it is confusing me.