Answer: -0.7
Explanation:
We know that when the absolute value of correlation coefficient 'r' is nearest to 1 then then we say that it represents the strongest correlation.
From the given options, the absolute value of -0.5=0.5
The absolute value of -0.7=0.7
The absolute value of -0.4=0.4
The absolute value of -0.6=0.6
We can see that the absolute value of -0.7 i.e. 0.7 is nearest to 1.
Therefore , the value of r =-0.7 represents the strongest correlation.