In research described in the text, niedenthal and others (2012) related pacifier use during infancy to impaired socioemotional development later on. however, the researchers stated that "the studies . . do not allow causal conclusions, as the children were not randomly assigned to pacifier use." based on this information, one can infer that the studies were rather than

Based on this information, one can infer that the studies were correlational, rather than experimental.

Correlational research simply defines if there is a relationship between two variables (covariation). This study greatly differs with experimental studies. Experimental studies is a method where treatments( independent variable)  are applied and the effects(dependent variable) are observed and recorded.

did mary wollstonecraft believe was a natural ingredient for women’s happiness?

so you should go with

a. strong

all of them lol cause theres no map