[单选题]

The following suggestions increase 'programs' (69) and make them easier to Maintain：
1．Use a standard indention technique，blank lines，form. feeds，and spaces．
2．Insert plenty of (70) into your code．
A．reliability
B．security
C．readability
D．usability

The following suggestions increase 'programs' (69) and make them easier to Maintain：1．Use a standard indention technique，blank lines，form. feeds，and spaces．2．Insert plenty of (70) into your code．A．reliabilityB．securityC．readabilityD．usability