The triple bond in carbon monoxide consists of 

$ \textbf{(A) } \text{3 sigma bonds}\qquad$

$\textbf{(B) } \text{2 sigma bonds and 1 pi bond}\qquad$

$\textbf{(C) } \text{1 sigma bond and 2 pi bonds}\qquad$

$\textbf{(D) } \text{3 pi bonds}\qquad$
1. **Determine the total number of valence electrons:**
   - Carbon (C) has 4 valence electrons.
   - Oxygen (O) has 6 valence electrons.
   - Therefore, the total number of valence electrons in carbon monoxide (CO) is \(4 + 6 = 10\).

2. **Apply the octet rule:**
   - Both carbon and oxygen need 8 electrons to satisfy the octet rule.
   - To achieve this, a triple bond is formed between carbon and oxygen.

3. **Identify the types of bonds in a triple bond:**
   - According to bonding rules, the first bond formed between two atoms is always a sigma (σ) bond.
   - Any additional bonds are pi (π) bonds.
   - Therefore, in a triple bond, there is 1 sigma bond and 2 pi bonds.

4. **Conclusion:**
   - The triple bond in carbon monoxide consists of 1 sigma bond and 2 pi bonds.

\[
\boxed{\text{C}}
\]