Software engineering is the study and application of engineering to the （ ） , development and maintenance of software.

题干中提到"Software engineering is the study and application of engineering"，表示软件工程是工程学科的研究和应用。接着提到"development and maintenance of software"，表示软件的开发和维护。因此，空格处应填入与软件设计相关的词汇，答案为D，即"design"。