What does the core in DevSecOps involve when it comes to 2 important concepts/methodology to secure app development?

a) Short periods of app development that results in a prototype to be exposed for penetration testing

b) Test-automation and continuous integration

c) Including the client/end user in defining and validating the security requirements

d) Security-awareness training for relevant developers

e) Easy use of secure app development applications, even though they are not commonly known or mature