The range of a cordless telephone refers to the maximum distance over which it can operate effectively without losing signal quality or experiencing dropouts. The range is influenced by several factors, including the frequency band used, the power output of the base station, and the presence of obstacles or interference.

Factors Affecting the Range of a Cordless Telephone:

1. Frequency Band:
- Cordless telephones typically operate in the 900 MHz, 2.4 GHz, or 5.8 GHz frequency bands.
- The higher the frequency, the shorter the range, as higher frequencies are more easily absorbed or scattered by obstacles such as walls or furniture.

2. Power Output:
- The power output of the base station directly affects the range of the cordless telephone.
- A higher power output allows the signal to travel further, resulting in a larger range.

3. Obstacles and Interference:
- Obstacles such as walls, floors, or other structures can attenuate the signal and reduce the range of the cordless telephone.
- Other devices operating in the same frequency band, such as Wi-Fi routers or microwave ovens, can cause interference and degrade the signal quality, resulting in a shorter range.

Explanation of Correct Answer:

The correct answer to this question is option 'C' - 100 m. Cordless telephones typically have a range of 100 meters, which is significantly shorter than the ranges of other wireless communication devices like Wi-Fi routers or cellular phones. This limited range is mainly due to the frequency band used by cordless telephones, which is typically 900 MHz or 2.4 GHz.

At these frequencies, the signal is easily attenuated by obstacles like walls or furniture, resulting in a reduced range. Additionally, the power output of cordless telephones is usually lower compared to other devices, further limiting the range.

It is important to note that the range mentioned may vary depending on the specific model and manufacturer of the cordless telephone. Some models may have a slightly higher or lower range due to variations in design and technology.