Ted along with George and Tim are partners in an architectural firm. They meet with their advisor and ask about the kind of agreement they should use to ensure that, upon the death of one, the remaining owners would purchase the deceaseds interest in the business. Their advisor explains that, if this is the arrangement they seek, then they should enter into a$($n$)$:a$.$ buy$-$sell agreement.b$.$ cross$-$purchase agreement.c$.$ arms$-$length agreement.d$.$ entity agreement.