Point out the technique, which is not useful for the detection of can…

The correct answer is Option (2) → DNA fingerprinting

Cancers of internal organs are detected by imaging techniques that show the inside of the body: radiography (X-rays), CT and MRI.

Option (1) X-rays — Useful for detection.

Option (2) DNA fingerprinting — Not useful for detection. It compares repetitive DNA sequences to identify persons, as in forensics and paternity tests; it does not find tumours.

Option (3) Computed tomography — Useful for detection.

Option (4) Magnetic resonance imaging — Useful for detection.

Note: A similar question was also asked in CUET (UG) 2025 on 26-05-2025 (Slot 2).

NCERT Extract:
Cancer – “… Cancer detection and diagnosis : Early detection of cancers is essential as it allows the disease to be treated successfully in many cases. Cancer detection is based on biopsy and histopathological studies of the tissue and blood and bone marrow tests for increased cell counts in the case of leukemias. In biopsy, a piece of the suspected tissue cut into thin sections is stained and examined under microscope (histopathological studies) by a pathologist. Techniques like radiography (use of X-rays), CT (computed tomography) and MRI (magnetic resonance imaging) are very useful to detect cancers of the internal organs. Computed tomography uses X-rays to generate a three-dimensional image of the internals of an object. MRI uses strong magnetic fields and non-ionising radiations to accurately detect pathological and physiological changes in the living tissue.”
DNA Fingerprinting – “… DNA Fingerprinting is a technique to find out variations in individuals of a population at DNA level.”