4 15% 4. Lockheed Martin Corporation makes aircraft instrumentation. Its basic navigation radio requires $85 in variable costs and requires $3,300 per month in fixed costs. Lockheed sells 50 radios per month. If the Lockheed upgrades the radio further to enhance its functionality, it will require an additional $15 per unit of variable costs, plus an increase in fixed costs of $1,800 per month. The current price of the radio is $295. The marketing manager is sure that they can charge $375 for the improved version. Should Lockheed further process