In the economy E: An apple producer sells $1500 apples directly to consumers, $800 to restaurant A and $1000 to restaurant B. Restaurant A uses $800 apples to produce $2000 apple cakes, and it sells all apple breads to restaurant B. Restaurant B uses $1000 apples and $2000 apple cakes to make $5000 applecakes. Then, all apple cakes are sold to consumers. The government provides safety services, including the army, valued at $2000. (a). What is the GDP of economy E?