With reference to learning unit $12,$ the term barrier function can be defined as:

a$.$The ability of a barrier to intervene into an accident to eliminate or amplify loss.

b$.$The ability of a barrier to intervene into an accident to eliminate or reduce loss.

c$.$The ability of a barrier to intervene into an accident to eliminate or increase loss.

d$.$The ability of a barrier to intervene into an accident to eliminate or add to loss.