Nucleic Acid Hybridization Assays Are Normally Carried Out Under Relaxed

Multiple Choice

Nucleic acid hybridization assays are normally carried out under relaxed hybridization stringency (to maximize the chances of heteroduplex formation) but afterwards, washes are carried out that can be designed to favor perfectly matched sequences only by changing some parameter. Which, if any, of the following changes would be consistent with that aim?

A) An increase in temperature.
B) An increase in salt concentration.
C) An increase in the concentration of a polar molecule, such as urea or formamide.