When correlation between two variables is very strong, the correlation coefficients will be:-

**Core Concept**
A correlation coefficient measures the strength and direction of the linear relationship between two variables. It ranges from -1 (perfect negative correlation) to 1 (perfect positive correlation), with 0 indicating no correlation.

**Why the Correct Answer is Right**
When the correlation between two variables is very strong, the correlation coefficient will be close to either 1 (positive correlation) or -1 (negative correlation). This is because a strong correlation indicates a consistent and predictable relationship between the variables. For example, in a study examining the relationship between systolic blood pressure and cardiovascular disease, a strong positive correlation would indicate that as systolic blood pressure increases, the risk of cardiovascular disease also increases.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because a correlation coefficient of 0 indicates no correlation between the variables, not a very strong correlation.
**Option B:** This option is incorrect because a correlation coefficient of -1 indicates a perfect negative correlation, not just a very strong correlation.
**Option C:** This option is incorrect because a correlation coefficient of 1 indicates a perfect positive correlation, not just a very strong correlation.

**Clinical Pearl / High-Yield Fact**
A strong correlation between two variables does not necessarily imply causation. It is essential to consider other factors, such as confounding variables and bias, when interpreting the results.

**Correct Answer: B. -1**