Answer:
The correct answer is letter "A": The convenience yield is always positive or zero.
Explanation:
The convenience yield reflects the premium of possessing an asset instead of one of its derivates or contracts. This situation arises in front of inverted markets, where holding the asset itself may bring more profits than purchasing a derivate of the same asset.
The convenience yield tends to be positive or zero because the prices of assets cannot fall below zero. In other words, they are not negative.