**Core Concept**
The diagnosis of syphilis involves a two-step approach: a non-treponemal screening test to detect antibodies against lipoidal material (cardiolipin) released from damaged host cells, followed by a confirmatory test to detect antibodies against specific treponemal antigens.

**Why the Correct Answer is Right**
The Fluorescent Treponemal Antibody Absorption (FTA-ABS) test is a treponemal-specific test that detects IgG antibodies against Treponema pallidum, the causative agent of syphilis. This test is highly specific and is used as a confirmatory test for syphilis, especially in cases where the initial non-treponemal test (e.g., VDRL) is positive but the patient's clinical presentation is unclear. The FTA-ABS test uses a fluorescent-labeled antibody to detect the presence of specific IgG antibodies against T. pallidum.

**Why Each Wrong Option is Incorrect**
**Option A:** VDRL (Venereal Disease Research Laboratory) is a non-treponemal test that detects antibodies against lipoidal material released from damaged host cells, not specific treponemal antigens, making it a screening test rather than a confirmatory test.
**Option C:** RPQ (Rapid Plasma Reagin) is another non-treponemal test similar to VDRL, used for screening purposes, not for confirmatory diagnosis.
**Option D:** None is incorrect because there is a correct answer among the options.

**Clinical Pearl / High-Yield Fact**
The FTA-ABS test remains positive for life, even after effective treatment of syphilis, which is why it is not used for monitoring treatment response. This is in contrast to non-treponemal tests, which can become negative after successful treatment.

**✓ Correct Answer: B. FTA-ABS**