Final answer:
Without additional context, 'r' cannot be determined for the Democratic Republic of the Congo. It might refer to a correlation coefficient, but the question does not provide sufficient information to select an option accurately.
Step-by-step explanation:
The letter r usually denotes the correlation coefficient in statistics, which measures the strength and direction of a linear relationship between two variables on a scatterplot. The value of r ranges from -1 to +1. Without a specific context from the provided information, I cannot determine what r refers to regarding the Democratic Republic of the Congo. However, considering the options given and the common use of r as the correlation coefficient, we can infer that the question might be asking for the correlation coefficient related to some data concerning the Democratic Republic of the Congo. Given that 'r' is typically a decimal value when describing a correlation coefficient, options A and B are more plausible than C and D. However, since there's no information directly linking the options to specific data about the Democratic Republic of the Congo, it's not possible to accurately determine r without additional context.