Redundancy is the grammatical error in the title. Using the words 'relationship between' and 'correlation' is redundant/unnecessarily repetitive. (Correlation is a mutual relationship or connection between two or more things).
B, Redundancy<span> is the grammatical error in the title. Using the words 'relationship between' and 'correlation' is redundant/unnecessarily repetitive. (Correlation is a mutual relationship or connection between two or more things).</span>