Which of the following is most likely to occur in the short run if there is an unanticipated decrease in aggregate demand due to a reduction in business and consumer optimism （）

A. An increase in the rate of unemployment.

B. An increase in real GDP.

C. A higher rate of inflation.

个人防护装备所涉及的防护部位主要包括眼睛、头、面部、躯体、手足、耳及呼吸道。