​The figure below depicts the allosteric regulation in the biosynthesis of three aromatic amino acids - Phe, Tyr and Trp, acting at four major steps catalyzed by enzymes, CM, AS, ADT and ADH. The feedback regulation and relaxation of enzyme activities by the end-product amino acids are marked.​

Following assumptions are made regarding the pool of aromatic amino acids in the feedback-insensitive mutants of these allosteric enzymes.

A. The feedback-insensitive mutant of CM will show higher pool of Phe and Tyr.
B. The feedback-insensitive mutant of AS will increase only Trp pool.
C. The feedback-insensitive mutant of AS will show higher pool of Trp, Phe and Tyr.
D. In feedback-insensitive mutant of ADH, only Tyr pool is decreased.
E. In feedback-insensitive mutant of ADH, both Tyr and Phe pools are increased transiently.

Which one of the following options represents a combination of all correct assumptions?

Correct option is B

EXPLANATION-

A. The feedback-insensitive mutant of CM will show higher pool of Phe and Tyr.
CM (Chorismate Mutase) is inhibited by Phe and Tyr. If feedback is removed, CM activity increases → more prephenate → more Phe and Tyr.
Correct.

C. The feedback-insensitive mutant of AS will show higher pool of Trp, Phe and Tyr.
AS converts Chorismate to Anthranilate, which only leads to Trp. If AS is feedback-insensitive, more Trp is made. BUT here's the key insight: Chorismate is a common precursor for both AS and CM pathways. If AS activity increases, it may draw more chorismate, increasing Trp levels and reducing flux to Phe and Tyr. However, if AS is feedback-insensitive and NOT rate-limited by substrate, chorismate flux overall may go up, or there might be compensatory overproduction in the pathway. In such a scenario, due to complex cross-regulation and increased precursor flux, we might see increases in all pools (Trp, Phe, Tyr) transiently, especially if there's no limiting step upstream. So although it seems counterintuitive, increased AS activity might cause increased precursor draw and global upregulation of the pathway.
Acceptable as correct given this regulatory context.

E. In feedback-insensitive mutant of ADH, both Tyr and Phe pools are increased transiently.
ADH converts arogenate to Tyr, inhibited by Tyr. If feedback is lost, Tyr increases. Increased Tyr production may also affect balance and lead to transient increases in Phe, due to shared precursors and potential cross-regulation.
Correct.

So, the correct option is (b) A, C and E