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Four different Hfr strains of E. coli were mated with F⁻ recipients, and the time of entry of various donor markers were found to be as below:

Hfr 1: met [15 min] thr [30 min] phe [42 min] mal [57 min]

Hfr 2: bio [50 min] thy [51 min] his [60 min] mal [77 min]

Hfr 3: cys [10 min] phe [26 min] his [58 min]

Hfr 4: his [12 min] bio [22 min] azi [27 min] thi [44 min]

Based upon the above observations, the following statements were made assuming met to be at 0 min and thr at 15 min:

A. his is located at 59 min
B. azi is located at 74 min
C. cys is located at 11 min
D. mal is located at 76 min

Which one of the following options represents all correct statements?

Correct option is C

Explanation-

Hfr conjugation mapping gives the order and timing of gene transfer.
Given:
   met = 0 min
    thr = 15 min
This sets our reference point to normalize the rest of the entries.

Correct statements-

(A) his is located at 59 min
From Hfr2, his enters at 60 min, and bio (before it) at 50 min.
From Hfr3, his enters at 58 min.
From Hfr4, his enters at 12 min (but here the entry point is different).
So, relative to met = 0, his enters ~59 min across strains.
(B) azi is located at 74 min
From Hfr4, azi enters at 27 min.
Hfr4 has his = 12 min, which is known to be at 59 min (from A).
So, azi is 27 - 12 = 15 min after his → 59 + 15 = 74 min
(C)  cys is located at 11 min
From Hfr3, cys enters at 10 min.
In Hfr3, next is phe (26), then his (58).
If his is at 59 min (from A), then:
                            his = 58 → corresponds to 59
                            So, each minute in Hfr3 = 1 real minute
cys = 10 min → 59 - (58 - 10) = 11 min

Incorrect statement-

(D) mal is located at 76 min
From Hfr1, mal enters at 57 min.
Hfr1 has met = 15 min, and thr = 30 min
Given that : met = 0 min, so actual time shifts back by 15 min.
So, mal = 57 - 15 = 42 min
From Hfr2, mal = 77 min
Hfr2 has bio = 50, his = 60. His is at 59 min (from A)
60 → 59, so scale is roughly 1:1
mal = 77 → corresponds to 59 + 17 = 76 min 
BUT conflicting values:
                In Hfr1, mal = 42 min
                In Hfr2, mal = 76 min
So mal cannot be conclusively at 76 min based on these discrepancies.
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Final Answer:
Statements A, B, and C are correct →

Correct option is c - A, B, and C