A pure culture of Escherichia coli was streaked on a plate to get single isolated colonies. The plasmid DNA from two such colonies was individually isolated. The DNA were then individually treated with EcoRI (P and Q) or double digested with $E c o \mathrm{RI}+\operatorname{Hind} \mathrm{III}\left(\mathbf{P}^{\prime}\right.$ and $\left.\mathrm{Q}^{\prime}\right)$. The digested DNA were electrophoresed on an agarose gel and the pattern of the linear DNA so obtained is depicted in the figure below. Patterns $\mathbf{P}$ and $\mathbf{P}^{\prime}$ are obtained for DNA from colony 1 and are as expected for the original DNA sequence of the plasmid. The best reason for the differing pattern in $Q^{\prime}$ is because the plasmid DNA from colony 2 has a mutation____

• Correct answer
  A

  resulting in another HindIII site
• B

  at its original EcoRI site
• C

  at its original HindIII site
• D

  resulting in another EcoRI site

Hence, the correct answer is option: 'A'.