Which factors are exclusively involved in the intrinsic pathway of coagulation?

The intrinsic pathway of coagulation is primarily activated by factors contained within the blood itself, initiating a cascade that leads to the formation of a blood clot. The factors involved in this pathway include Factor XII, Factor XI, Factor IX, and Factor VIII.

Choosing the answer that lists only factors 8, 9, 11, and 12 aligns perfectly with the components that are classified under the intrinsic pathway. Factor VIII interacts with Factor IX to form a complex that ultimately activates Factor X, whereas Factors XI and XII also contribute to this process.

The other options include factors that either do not belong to the intrinsic pathway or encompass elements that are part of different coagulation pathways, such as the extrinsic or common pathways. For instance, factors like prothrombin and vitamin K-dependent factors or composite groups of factors mentioned in the other choices, do not isolate the intrinsic pathway components effectively. Thus, the specificity and exclusivity of the listed factors in the chosen answer illustrate their central roles within the intrinsic coagulation cascade.