Which of the following is not a possible explanation for why significant deviations from covered interest parity were observed during the recent global financial crisis? select one:
a. a crisis-induced worsening of existing impediments to financial trade .
b. an inability of cash-poor institutions to be able to engage in covered transactions.
c. a decline in trust among banks that trade bonds internationally.
d. crisis-induced increases in mobility of an substitutability among internationally traded bonds.