Which of the following titles is suitable for a research paper?with the key words “unmanned air vehicle” and “ engine”

A.Design, build and test anunmannedairvehicle

B.Improved efficiency of an unmanned air vehicle IC engine using computational modelling and experimental verification

C.Unmanned air vehicles under external impact

D.Engine-integrated solid oxide fuel cells for efficient electrical power generation on aircraft

正确答案：Improved efficiency of an unmanned air vehicle IC engine using computational modelling and experimental verification