To solve this problem, we need to identify which immune response is responsible for the rejection of a kidney graft. Let's analyze each option:$\newline \bullet$Option 1: Auto-immune response$\newline$ - An auto-immune response occurs when the immune system mistakenly attacks the body's own cells.$\newline$ - This is not typically involved in graft rejection, which involves foreign tissue.$\newline \bullet$Option 2: Humoral immune response$\newline$ - The humoral immune response involves antibodies produced by B cells.$\newline$ - While antibodies can play a role in graft rejection, the primary mechanism is not humoral.$\newline \bullet$Option 3: Inflammatory immune response$\newline$ - Inflammation is a general immune response to injury or infection.$\newline$ - It is part of the response but not the specific mechanism for graft rejection.$\newline \bullet$Option 4: Cell-mediated immune response$\newline$ - The cell-mediated immune response involves T cells that directly attack and destroy foreign cells.$\newline$ - This is the primary mechanism responsible for the rejection of transplanted organs, such as a kidney graft.$\newline$Therefore, the correct option is Option 4: Cell-mediated immune response.