A metaphor does not need to use like or as. A metaphor typically says one thing is another thing, but doesn’t always suggest that they are the same thing. Symbolism is similar to metaphor, but symbolism is usually implied, while metaphor is explicit. For example, “Juliet is the sun” is a metaphor, but not a symbol, while heavy rain could be a reference to Noah’s Ark and be a symbol of cleansing. In the second case, the comparison is not stated, but is implied.
Based on these definitions, B and C are definitely wrong, but neither A or D is completely right. I’d still say that D is the best answer though.