Which is the appropriate tool to identify the possible correlation two elements in aprocess?

A scatter diagram (also called a scatter plot or X-Y diagram) is specifically designed to plot paired data points for two variables, allowing the analyst to visually determine whether a correlation exists between them - positive, negative, or none. It is one of the seven basic quality tools in the PMBOK Guide and is the standard technique for investigating relationships between two process elements.

A cause and effect diagram (Ishikawa or fishbone) maps the potential root causes of a single problem or effect - it does not quantify or visualize correlation between two variables.

A histogram displays the frequency distribution of a single variable across categories or intervals, not the relationship between two separate variables.

Control charts monitor a single process variable over time to detect trends or out-of-control conditions, not to identify correlations between two distinct process elements.