Haploid spores of sac fungi occur in

Options

A. Ascocarp
B. Basidiocarp
C. Basidium
D. Ascus.

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks where haploid spores of sac fungi occur. Sac fungi belong to the group Ascomycetes.

2. **Identifying the Options**: The options provided are:
- Option 1: Ascocarp
- Option 2: Basidiocarp
- Option 3: Basidium
- Option 4: Ascus

3. **Analyzing Each Option**:
- **Ascocarp**: This is the fruiting body of Ascomycetes that contains asci. While it is related to the production of spores, it does not directly contain the haploid spores themselves.
- **Basidiocarp**: This is the fruiting body of Basidiomycetes, which produces basidiospores, not haploid spores from sac fungi.
- **Basidium**: This structure is involved in the reproduction of Basidiomycetes and produces basidiospores, which are also not haploid spores of sac fungi.
- **Ascus**: This is the structure within the Ascomycetes where haploid spores are formed. It contains the meiotic products of a single diploid nucleus, resulting in haploid spores.

4. **Conclusion**: The correct answer is **Option 4: Ascus**, as this is where haploid spores of sac fungi are produced.