Answer:
Pseudobulbar affect (PBA) is a condition that is marked by uncontrollable and at times, inappropriate laughing or crying. While it can be explained that Lena is crying at her brother's wedding because she may be happy for him, it is more peculiar that Carrie cannot stop laughing. Carries may have PBA, and thus, has no control over the fact that she is laughing at the wedding.
Explanation:
