Answer:
c. dispositional
Explanation:
The key words here are "Believing that", so it's not based on facts (of what we know), but is just a feeling, an impression, most importanty, is that the person believes it's his/her fault. So, it's clearly an internal attribution.
If that significant other would have made a statement to that effect, it would have been for him/her an external attributions.
External and situational attributions are the same, just another name for it.
