What can be inferred about someone who frequently changes their opinion?

The inference that someone who frequently changes their opinion is fickle is accurate because the term "fickle" describes a person who is changeable, especially in their loyalties, interests, or affections. When an individual regularly alters their stance or viewpoint, it suggests a lack of consistency in their beliefs, which aligns perfectly with the notion of being fickle. This tendency to frequently change opinions can stem from various factors, such as indecisiveness, being easily influenced by others, or a lack of strong convictions.

In contrast, the other choices do not accurately capture this behavior. For instance, being steadfast indicates a firm and unyielding adherence to one's beliefs, which contradicts the notion of changing opinions. Being knowledgeable suggests a depth of understanding and insight, typically leading to well-considered opinions rather than frequent changes. Shyness relates to one's comfort in social situations and does not inherently connect to the behavior of changing opinions. Therefore, the term "fickle" is the most fitting descriptor for someone who often shifts their opinions.