According to the article, 'Diversity Push Barely Budges Corporate Boards to $12\mathrm{.}5\%,$ Survey Finds, the Board Challenge campaign calls on companies to$,$

Select one:

a$.$

Add a board mandate for diversity within their company

b$.$

Adhere to higher principles of diversity and inclusion

c$.$

Assess their internal board composition

d$.$

Add a Black director within the next $12$ months