The answer is c.
You can immediately rule out a because it's not even close. It can't be b or d because it doesn't really give enough information to cause those emotions. In other words it is vague while still peaking the reader's interest, so it mus be mysterious.
The dust of snow<span> is the symbol of natural joy and energy. It </span>means<span> passing through the sad and depressing moments the </span>poet<span> is entering into the time full of joy and optimism.</span>