Final answer:
DMS footprinting is the technique used to evaluate protein-DNA contacts on single-stranded DNA by protecting guanine bases from methylation when a protein is bound.
Step-by-step explanation:
The technique used to evaluate protein: DNA contacts on single-stranded DNA is DMS footprinting (option C). This method utilizes dimethyl sulfate (DMS) which can methylate guanine bases within the DNA strand. When a protein is bound to DNA, it protects certain guanine bases from methylation.
After treating the DNA with DMS, cleavage at the methylated guanines allows for the identification of protein-bound regions due to the absence of cleavage in these protected areas. This contrasts with methods such as filter binding assays, GST pull-down assays, and DNase I footprinting, which are suited for different contexts and may involve double-stranded DNA or protein-protein interactions rather than direct protein-DNA contacts on single-stranded DNA.