The amount of economic aid E (in millions of dollars) a country receives from the USA is related to the military aid x (in millions of dollars) it is also receiving by the function E(x)=10+sqrt(5x³+x²⁾ The military aid is currently $18 million a year, but is decreasing by $4 million per year; how is economic aid changing?

• A. - $57 million / year
• B. - $56 million / year
• C. - $55 million / year
• D. - $54 million / year