Which of the following conditional statements is equivalent to "Either it is snowing or raining or I will wear my coat"?

a. If it is not snowing and not raining, then I will wear my coat.
b. If it is not snowing or not raining, then I will wear my coat.
c. If it is not snowing and raining, then I will wear my coat.
d. If it is snowing and not raining, then I will wear my coat.