Select the option that includes liverworts only.

Options

A. Riccia, Marchantia
B. Riccia, Funaria
C. Polytrichum, Marchantia
D. both a and c

Explanation

To solve the question of selecting the option that includes liverworts only, we can follow these steps:

### Step 1: Understand the Definition of Liverworts
Liverworts are non-vascular plants that belong to the division Marchantiophyta. They are typically small, green plants that thrive in moist environments.

### Step 2: Analyze the Given Options
We need to evaluate each option provided to determine which one includes only liverworts.

### Step 3: Evaluate Option 1
- **Option 1: Riccia and Marchantia**
- Both Riccia and Marchantia are known to be liverworts.
- **Conclusion**: This option is correct as it includes only liverworts.

### Step 4: Evaluate Option 2
- **Option 2: Riccia and Pheneria**
- Riccia is a liverwort, but Pheneria is classified as a moss.
- **Conclusion**: This option is incorrect as it includes a moss.

### Step 5: Evaluate Option 3
- **Option 3: Polytrichum and Marchantia**
- Marchantia is a liverwort, but Polytrichum is also classified as a moss.
- **Conclusion**: This option is incorrect as it includes a moss.

### Step 6: Evaluate Option 4
- **Option 4: Both A and C**
- Since Option A is correct (both are liverworts) and Option C is incorrect (one is a moss), this option cannot be correct.
- **Conclusion**: This option is incorrect.

### Final Conclusion
After evaluating all the options, the only option that includes liverworts only is **Option 1: Riccia and Marchantia**.