Fajar has six different meals from a meal delivery service. Three meals include chicken, two meals include beef, and one meal is vegetarian. Fajar will eat one of these meals per day for the next six days. How many different arrangements of meals are possible if

a) The meals can be eaten in any order?

b) The first meal must include chicken and the last meal must include beef?

c) The first two meals must include beef and the last meal must be vegetarian?