Recombinant DNA technology involves the insertion of a specific gene from one organism into the DNA of another organism. This process requires the use of restriction enzymes to cut both the vector DNA and the source DNA at specific sites, creating compatible ends that can then be joined together.

Here's a breakdown of the options provided:

Option A: Hind II, Hind II

Both the vector DNA and the source DNA are cut with Hind II. However, since Hind II would cut both DNAs at the same sequence, it may not necessarily create sticky ends that are compatible for recombination.

Option B: Hind II, Alu I

Using Hind II for the vector DNA and Alu I for the source DNA means they are cut with different restriction enzymes. This typically wouldn’t create compatible ends for recombination.

Option C: Hind II, EcoR I

Similar to Option B, Hind II for the vector DNA and EcoR I for the source DNA won’t create compatible ends, as different enzymes recognize and cut at different sequences.

Option D: Hind II, BamHI

In this option, Hind II cuts the vector DNA and BamHI cuts the source DNA. Like Options B and C, using different restriction enzymes typically won’t create compatible ends for recombinant DNA formation.

Therefore, the correct answer is:

Option A: Hind II, Hind II

Because using the same restriction enzyme for both the vector and the source DNA increases the likelihood of generating compatible "sticky" ends that can be joined together to form a recombinant DNA molecule.