The data below was obtained from the following research article:

Brunet YR, Zoued A, Boyer F, Douzi B, Cascales E. The Type VI Secretion TssEFGK-VgrG Phage-Like Baseplate Is Recruited to the TssJLM Membrane Complex via Multiple Contacts and Serves As Assembly Platform for Tail Tube/Sheath Polymerization. PLoS Genet.

In this experiment, the TssMCFL protein was immunoprecipitated from cells overexpressing the proteins indicated at the top of the figure and loaded on a gel (lanes indicated by IP), and associated proteins were detected by Western blot. Lanes indicated with "T" have been loaded with total protein lysates that have not undergone immunoprecipitation. The two Western blots shown detect either TssGVS (marked GVS), or TssMCFL (marked MCFL).

What is the experimental purpose of lane 2? Select the best answer.

a.

This lane is experimental: it provides a result that illuminates how these proteins behave

b.

This lane confirms that the antibody used for immunoprecipitation does not bind TssGVS

c.

This lane confirms that the antibody used for immunoprecipitation does bind TssMCFL

d.

This lane confirms the presence of specific proteins in the total cell lysate