A values$-$based ethics culture is best described by which of the following statements?

a$.$ It excludes Upper Management Board, but relies solely on the Board of Directors to add to general value statements by formulating spec business units $($SBU$).$

b$.$ It is based solely on transparency to help employees identify and deal with ethical issues.

c$.$ It is based solely on the Office of Best Practices to help employees identify and deal with ethical issues.

d$.$ It relies upon an explicit mission statement that defines the core values of the firm.

e$.$ It excludes the Board of Directors, but relies solely on Upper Management to add to general value statements by formulating specific valu units $($SBU$).$