Let's analyze each pair to find the incorrect match(es).
(B) M'Naghten case --- defence of insanity: This is correctly matched.
The M'Naghten Rules are the famous legal test for criminal insanity in many common law jurisdictions.
(D) R v.
Dudley & Stephens --- defence of necessity: This is correctly matched.
This famous case of shipwreck and cannibalism is the leading authority on the limits of the defense of necessity.
(A) R v.
Wheat and Stocks --- mistake of law: This is incorrectly matched.
This case, similar to R v.
Tolson, deals with the offense of bigamy and is a key case on mistake of fact, not mistake of law.
(C) R v.
Tolson --- defence of infancy: This is incorrectly matched.
The case of R v.
Tolson is the landmark judgment on the defence of mistake of fact.
Mrs.
Tolson remarried, genuinely believing her first husband, who had been missing for years, was dead.
The defence of infancy relates to the age of the accused.
Both (A) and (C) are incorrectly matched.
In a single-choice question context, both are validly incorrect, indicating a possible flaw in the question design.