price of saffron

The demand for saffron is highly elastic. The demand for cigarettes is highly inelastic. The demand for peanut butter is unit-elastic.
a. If saffron producers reduce the price of saffron, what will happen to total revenue as a result? Will marginal revenue be positive, zero, or negative?
b. If cigarette makers reduce the price of cigarettes, what will happen to total revenue as a result? Will marginal revenue be positive, zero, or negative?
c. If peanut butter producers reduce the price of peanut butter, what will happen to total revenue as a result? Will marginal revenue be positive, zero, or negative?

price of saffron