The Disadvantage of Batch Fermentations, as Opposed to Continuous Feed

The disadvantage of batch fermentations, as opposed to continuous feed systems, is that

A) there is a limit to the amount of product formed since all materials are added to the fermentor at the beginning.
B) the end product is not as pure as the product made by the continuous feed process.
C) it is small scale production of a product.
D) new substrate must be added to the fermentor continuously for the fermentation to continue.