Correct option is A
Explanation-
The ABC model defines the identity of the floral whorls:
A alone = Sepals (1st whorl)
A + B = Petals (2nd whorl)
B + C = Stamens (3rd whorl)
C alone = Carpels (4th whorl)
In the agamous (ag) mutant:
The C function (which specifies stamens and carpels) is lost.
This results in the expansion of A and B functions into the inner whorls.
As a result, instead of stamens and carpels, the plant produces additional whorls of sepals and petals.
This causes a repeated pattern of sepals–petals–petals (and more) in a loop-like floral structure.
So, the correct answer is option a - agamous (ag).
Incorrect options-
Option b: apetala 1 (ap1)
Gene A is affected (partial or full loss of function)
Result:
No repeated petals.
Instead, flowers may look leafy or have missing petals.
Option c: apetala 3 (ap3)
Gene B is lost.
Result:
Flower don’t get extra petals, actually lose petals and stamens.
Pattern becomes more like: sepals–sepals–carpels–carpels.
Option d: Pistillata (pi)
Another B-function gene, like ap3.
Result: Similar to ap3 mutant.
Again, petals and stamens are lost, not repeated.
No “sepals–petals–petals” pattern seen.
