The problem asks for the value of $Y$ when $x = 6$, using the given regression equation $y = 0.85x + 3.35$.

We can solve this by substituting $x = 6$ into the equation.

$y = 0.85(6) + 3.35$

First, calculate $0.85 \times 6$:

$0.85 \times 6 = 5.1$

Now, add $3.35$ to $5.1$:

$y = 5.1 + 3.35 = 8.45$

So, the value of $Y$ when $x = 6$ is 8.45.

The correct answer is A. 8.45.

Would you like a detailed explanation on how this regression works or more insights into linear regression concepts? Here are five related questions for further exploration:

1. How is the slope of the regression line calculated?
2. What does the constant (3.35) in the equation represent?
3. How would you calculate the residual for $x = 6$?
4. How do you determine if this regression equation fits the data well?
5. How does the correlation coefficient relate to the regression equation?

Tip: In linear regression, the slope indicates the rate of change of $y$ for every unit increase in $x$, while the intercept shows the value of $y$ when $x = 0$.