Amensalism can be represented as :

In ecology, population interactions between two different species can be classified based on whether the interaction is beneficial, harmful, or neutral to each of the participating species. These effects are commonly represented by symbols:
• (+) represents a beneficial interaction where the species gains an advantage.
• (−) represents a harmful or inhibitory interaction where the species is negatively affected.
• (0) represents a neutral interaction where the species is completely unaffected.

Amensalism is a type of interspecific interaction where one species is harmed, inhibited, or destroyed, while the other species is neither benefited nor harmed (it remains unaffected).
Therefore, if we have two interacting species, Species A and Species B, amensalism can be represented as:
Species A (−) ; Species B (0) (or vice versa).

To understand this better, let us look at the other options to see how they represent different ecological relationships:
• Species A (+) ; Species B (+) represents Mutualism, where both species benefit from the interaction (for example, lichens representing an association between algae and fungi).
• Species A (−) ; Species B (−) represents Competition, where both species are adversely affected as they compete for the same limited resources.
• Species A (+) ; Species B (0) represents Commensalism, where one species benefits while the other remains unaffected (for example, an orchid growing as an epiphyte on a mango branch).

An everyday example of amensalism is the bread mold fungus Penicillium. It secretes penicillin, an antibiotic that kills or inhibits nearby bacteria (−), while the fungus itself remains unaffected (0) by the presence of the bacteria.