To find the cost of the granola mix, you can multiply the price per pound by the weight of the bag.
The granola mix costs $8.99 per pound and the bag weighs 7.8 pounds.
Cost = Price per pound × Weight Cost = $8.99 × 7.8
Calculating this:
\[ Cost = 8.99 \times 7.8 = 70.022 \]
So, the cost would be approximately $70.02.
The closest option from those provided is $72.