Antonella's liability is contingent on her explicit promise to both Richard and Carla. Without such a promise, she is not obligated to perform the duty. Here option B is correct.
Antonella becomes liable for nonperformance to both Richard and Carla only if she promises both Richard and Carla that she will perform Richard's duty.
When a duty is delegated, the delegatee, in this case, Antonella, assumes the responsibility to perform the duty as agreed upon with both parties involved. If Antonella explicitly promises both Richard and Carla that she will fulfill Richard's duty, she incurs a contractual obligation to both parties.
However, without such a promise, option b is also true, as Antonella is not obligated to perform the duty unless she agrees to do so. Here option B is correct.
Complete question:
Which of the following statements accurately describes Antonella's liability after Richard delegates a duty to her?
a. Antonella becomes liable for nonperformance to both Richard and Carla only if she promises both Richard and Carla that she will perform Richard's duty.
b. Antonella is not obligated to either Richard or Carla to perform the duty unless Antonella agrees to do so.
c. Antonella is liable only to Richard because that is who she has a contract with.
d. Antonella cannot create contractual rights in Carla.