This question refers to the "Claims Processing" case. A hospital processes claims and the insurance companies often reject them for coding errors. A process improvement team has been working on a project to reduce coding errors for the past $15$ months and the data for the number and type of coding errors can be downloaded from the link provided. Use this data to answer the question below.

Construct an XmR $($ImR$)$ chart by month for errors per claim. What can you say about the team's progress in reducing the number of errors per claim?

A The process is stable

B There are many out$-$of$-$control spikes

C There is an adverse shift in month $4$

D There is good progress showing a downward trend

E There is no evidence of improvement