In the current environment, air defense is made difficult by: Answer Options: A. Greater difficulty in predicting timing and sector of attack, and decreasing availability of airborne sensors B. Greater difficulty in predicting timing and sector of attack, greater stress on data collection and communications, and decreasing availability of airborne sensors C. Less reaction time, greater difficulty in predicting timing and sector of attack, and greater stress on data collection and communications D. Less reaction time and greater stress on data collection and communications