Final answer:
The correct complementary DNA sequence to GACTTGCA is CTGAACGT by applying the base-pairing rules. A typo is present since none of the options match the correct sequence.
Step-by-step explanation:
The complementary sequence of nucleotides to the original sequence of DNA GACTTGCA is found by applying the base-pairing rules where adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). Adding to the original sequence, the complement of guanine is cytosine, adenine is thymine, cytosine is guanine, and thymine is adenine.
The complementary sequence is therefore:
- G -> C
- A -> T
- C -> G
- T -> A
- T -> A
- G -> C
- C -> G
- A -> T
Putting it all together, the complementary sequence is CTGAACGT.
From the given options, however, none matches this correct complementary sequence exactly. This type of question often occurs in exams to test the student's understanding of DNA replication and base pairing. If there's an error or typo in the options given in the question, it should be reported to the instructor for clarification.