Short stretches of DNA used to identify complementary sequence in a sample are called:

Options

A. Probes
B. Markers
C. VNTRs
D. Primers

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about short stretches of DNA that are used to identify complementary sequences in a sample.

2. **Analyzing the Options**: The options provided are:
- Props
- Markers
- VNTRs (Variable Number Tandem Repeats)
- Primers

3. **Defining the Terms**:
- **Props**: These are short stretches of DNA or RNA that can bind to complementary sequences. They are often labeled for identification, typically emitting fluorescence.
- **Markers**: These are specific segments of DNA used for various purposes, but not specifically for binding complementary sequences.
- **VNTRs**: These are repeating sequences in DNA that are non-coding and used for genetic fingerprinting, but they do not serve the purpose of identifying complementary sequences.
- **Primers**: These are short sequences of nucleotides that provide a starting point for DNA synthesis, primarily used in PCR (Polymerase Chain Reaction).

4. **Identifying the Correct Answer**: Among the options, "props" (which refers to probes) are specifically designed to bind to complementary sequences, making them the correct answer.

5. **Final Answer**: The short stretches of DNA used to identify complementary sequences in a sample are called **probes**.

---