A Claimant in an Action Obtained an Engineer's Report and Served

A Claimant in an action obtained an engineer's report and served it on the Defendant. Subsequently the Claimant secured and disclosed another engineering report and served it on the Defendant. In relation to the first engineering report which is correct?

A) If the Claimant elects not to rely on the first expert, the Defendant may not use the first expert's report.
B) If the Claimant elects not to rely on the first expert, the Defendant may use the first report to rely on and use at trial.
C) The Defendant may only rely on the Claimant's first expert's report at trial if the Claimant agrees.
D) The Defendant may only rely on the Claimant's first expert's report at trial if the court grants permission.