Truman's Executive Order 9981 affected the military by

permitting women to serve.

guaranteeing benefits.

allowing younger soldiers.

ending segregation.

.

The correct answer is: "ending segregation"

The Executive Order 9981 was enacted by US President Harry S. Truman in 1948. It outlawed discrimination in terms of race, color, ethnicity, religious beliefes or national origin in the US Armed Forces. Therefore, this legal instrument was the base for enforcing the equal-rights provision that had already been included in the Reconstruction Amendments and for ending segregation for good in the US military services.

D. Execute Order 9981 affects the military by ending segregation