In Kamil and Balda's $(1985)$ study with food$-$caching nutcrackers, the researchers pre$-$determined which locations the birds could cache in order to control forQuestion $2$Select one:a$.$use of visual cuescross outb.Selecting caching sites controlled for all of these variables. cross outc.use of olfaction cues $($maybe$)$cross outd.preference for certain types of locations