A Second-To-Default (STD)basket Option Pays Off When Any One of the Companies

A second-to-default (STD) basket option pays off when any one of the companies in a credit basket defaults.The price of the STD basket increases when

A) The credit quality of any issuer in the basket improves.
B) The correlation of default across names in the basket increases.
C) The correlation of default across names in the basket decreases.
D) The volatility of credit spreads for names in the basket decreases.