Answer:
B. the massive cost and growing unpopularity of the Vietnam War
Explanation:
In his first State of the Union address in January 1964, President Lyndon B. Johnson requested that Congress announce an "unconditional war on poverty" and to point "not only to relieve the symptom of poverty, but to cure it and, above all, to prevent it".
Throughout the following five years, Congress passed enactment that changed American schools, propelled Medicare and Medicaid, and extended housing subsidies, urban development programs, employment and training programs, nourishment stamps, and Social Security and welfare benefits. These projects dramatically multiplied genuine government uses on wellbeing, training, and welfare, which developed to more than 15 percent of the federal budget by 1970.