The correct option is A is
It is to be kept in mind that Either, Neither, Each, Everyone, Many a, must be followed by a singular verb.
'Each of these spices' means each particular spice. So, we are referring to a singular noun. By the general convention, a singular noun takes a singular verb. Hence, Option A 'is' is correct and Option B "are' is incorrect.
Options C and D are incorrect as these verbs are irrelevant to the context.