A graph was plotted taking the temperature in `.^@C` along the X-axis and the corresponding temperature in Kelvin along the Y-axis. Which of the curves in Fig, 6.1 most correctly represents this behaviour?

Options

A.
B.
C.
D.

Explanation

To solve the problem, we need to analyze the relationship between temperature in degrees Celsius (°C) and temperature in Kelvin (K). The relationship is given by the formula:

\[ K = °C + 273 \]

### Step-by-Step Solution

1. **Understanding the Relationship**:
- The formula \( K = °C + 273 \) indicates that for every degree increase in Celsius, the Kelvin temperature increases by the same amount. This means that the relationship is linear.

2. **Identifying the Axes**:
- In the graph, the x-axis represents temperature in degrees Celsius (°C) and the y-axis represents temperature in Kelvin (K).

3. **Identifying the Equation Format**:
- The equation \( K = °C + 273 \) can be rewritten in the form of a straight line equation \( y = mx + c \), where:
- \( y \) is the temperature in Kelvin (K),
- \( x \) is the temperature in Celsius (°C),
- \( m \) is the slope of the line,
- \( c \) is the y-intercept.

4. **Determining the Slope and Intercept**:
- From the equation \( K = °C + 273 \):
- The slope \( m = 1 \) (indicating a 45-degree angle with respect to the x-axis).
- The y-intercept \( c = 273 \) (the point where the line crosses the y-axis).

5. **Analyzing the Graph Options**:
- Since the slope is positive (1), the graph should be an upward sloping line.
- The line should intersect the y-axis at \( K = 273 \) (when \( °C = 0 \)).
- We need to find the option that matches these characteristics: a straight line with a positive slope and a y-intercept at 273.

6. **Selecting the Correct Option**:
- After examining the provided options in Fig. 6.1, we look for a straight line that has a positive slope and intersects the y-axis at 273.
- The correct option will be the one that satisfies these conditions.

### Conclusion
The correct answer is **Option 1**, as it represents a straight line with a positive slope of 1 and a y-intercept at 273.