Commensalism
Parasitism
Mutualism
Amensalism
Commensalism refers to a relationship wherein one organism is benefitted while the other remains unaffected and is denoted by + 0. Amensalism refers to an association wherein one partner is inhibited while the other remains nearly unaffected and is denoted by - 0. Association of organisms which benefits one of the partners at the expense of the other is called parasitism and is denoted by + -. Mutualism is an association of organisms wherein both are benefitted and is denoted by + +. Therefore, the correct answer is Parasitism.