**Core Concept**
Fixation at a particular psychosexual stage, as described by Sigmund Freud, can lead to specific personality traits or psychological disorders. In this context, fixation refers to a situation where an individual's development is arrested at a particular stage, resulting in an excessive focus on the characteristics of that stage.

**Why the Correct Answer is Right**
Fixation at the anal stage is associated with the development of obsessive-compulsive disorder (OCD). During the anal stage, children between 1 and 3 years old focus on toilet training and the control of their bowel movements. According to Freud, fixation at this stage can lead to an excessive need for control and order, which are hallmark features of OCD. This fixation can result in an individual's preoccupation with rituals, perfectionism, and a strong need for symmetry and order.

**Why Each Wrong Option is Incorrect**
**Option A:** Oral fixation is associated with an excessive focus on oral activities such as eating, drinking, and talking. While oral fixation can lead to various personality traits, it is not directly linked to the development of OCD.
**Option C:** Phallic fixation, which occurs during the phallic stage (around 3-6 years old), is associated with issues related to sex and aggression. This fixation can lead to various psychological disorders, but it is not directly linked to OCD.
**Option D:** Genital fixation occurs during the genital stage (puberty onwards) and is associated with issues related to sex and relationships. While fixation at this stage can lead to various psychological disorders, it is not directly linked to OCD.

**Clinical Pearl / High-Yield Fact**
Freud's psychosexual stages are a theoretical framework that can help understand personality development and psychological disorders. However, it's essential to note that this theory has been largely discredited in modern psychiatry, and OCD is now understood to be a neurobiological disorder rather than a result of psychosexual fixation.

**✓ Correct Answer: B. Anal. Fixation at the anal stage is associated with the development of obsessive-compulsive disorder (OCD).**