The correct answer is $\boxed{\text{A) }+0.16}$.
The coefficient of correlation is a measure of the strength and direction of the linear relationship between two variables. It is calculated by taking the square root of the product of the two regression coefficients. In this case, the two regression coefficients are 0.8 and 0.2, so the coefficient of correlation is $\sqrt{0.8 \times 0.2} = +0.16$.
A positive coefficient of correlation indicates that there is a positive linear relationship between the two variables, meaning that as one variable increases, the other variable also tends to increase. A negative coefficient of correlation indicates that there is a negative linear relationship between the two variables, meaning that as one variable increases, the other variable tends to decrease. A coefficient of correlation of 0 indicates that there is no linear relationship between the two variables.
In this case, the coefficient of correlation is positive, which indicates that there is a positive linear relationship between the two variables. This means that as the first variable increases, the second variable also tends to increase.