The neurological disorder CANVAS is caused by intronic expansions of the AAGGG repeat in the gene RFC1, which is important for DNA replication. Healthy individuals generally have 11 repeats while CANVAS patients can have as many 2000 AAGGG repeats. Tufts' Dr. Sergei Mirkin wants to know if secondary structures are involved in the expansion of these repeats. Which structures should Dr. Mirkin focus his inquiry on? Select all that apply. A-DNA Hairpins Cruciforms Triplex DNA G-quadruplex DNA