Final answer:
Considering both kappa and lambda light chains, there are a total of four possible combinations for the light chain of an immunoglobulin molecule.
Step-by-step explanation:
When considering the total number of possibilities for the light chain in immunoglobulins, we need to account for the two different types of light chains: lambda and kappa. Each immunoglobulin molecule can have either two kappa light chains or two lambda light chains, but not a mixture of the two. Since there are only two types of light chains, and each immunoglobulin molecule must consist of two identical light chains, we have two possibilities for kappa and two for lambda. Therefore, there are a total of four possible combinations for the light chain of an immunoglobulin.