'Roquefort cheese' is known for its particular flavour. This characteristic flavour is achieved by ripening the cheese using:

Step-by-step solution

According to NCERT, different varieties of cheese are known by their characteristic texture, flavour and taste, the specificity coming from the microbes used. The 'Roquefort cheese' are ripened by growing a specific fungi on them, which gives them a particular flavour. Students often confuse this with Swiss cheese, which is ripened by a bacterium (Propionibacterium sharmanii). Thus, the correct biological agent for Roquefort cheese is a specific fungi. Answer: A specific fungi