**Core Concept**
De Clerambault's syndrome is a psychiatric condition characterized by a delusional belief that another person, often of higher social status, is in love with the individual. This delusional belief is a type of erotomania, where the affected person misinterprets social interactions and believes that the other person is reciprocating their feelings.

**Why the Correct Answer is Right**
De Clerambault's syndrome is a type of persecutory delusion, where the affected person believes that they are being loved by someone else. This delusion is often accompanied by a sense of grandiosity and a distorted view of reality. The condition is named after the French psychiatrist Gaëtan Gatian de Clérambault, who first described it in the early 20th century. The delusional belief is typically resistant to reason and evidence, and may lead to obsessive and intrusive thoughts, as well as social isolation.

**Why Each Wrong Option is Incorrect**
**Option A:** Ekbom's syndrome is actually known as delusional parasitosis, a condition where the affected person believes that they are infested with parasites or insects. This is a different type of delusional disorder.
**Option C:** Querulous paranoia is a type of paranoid personality disorder characterized by a pervasive distrust of others and a tendency to be litigious. While it shares some features with De Clerambault's syndrome, it is not the same condition.
**Option D:** Othello syndrome is a type of delusional disorder where the affected person believes that their partner is being unfaithful to them. This is a different type of delusional disorder, and is not characterized by a belief that someone is in love with them.

**Clinical Pearl / High-Yield Fact**
De Clerambault's syndrome is often seen in individuals with a history of trauma, stress, or social isolation. It is essential to approach these patients with empathy and understanding, as they may become defensive or aggressive when confronted with the reality of their delusional beliefs.

✓ Correct Answer: B. De Clerambault's syndrome