Read the following excerpt from a US court opinion:
```
for juror confusion about which role the lawyer is serving during trial. “A witness is required to testify on the basis of personal knowledge, while an advocate is expected to explain and comment on evidence given by others. It may not be clear [to the factfinder] whether a statement by an advocate-witness should be taken as proof or as an analysis of the proof.” Rule 3.7, Comment (2). See also Chapman Engineers v. Natural Gas Sales Co., 766 FSupp. at 957 (14) (“One of the strongest rationales for this lawyer-witness rule is to prevent jury confusion over the separate roles of an advocate and a witness.”). We find, however, that concerns about possible juror confusion are not relevant to pre-trial proceedings. See Culebras Enterprises Corp. v. Rivera-Rios, 846 F2d at 100-101 (II) ; Pyne v. Procacci Bros. Sales Corp. &c., 1997
```
What is the most suitable continuation to the opinion? Your options are:
A. holding that rule 37 does not prohibit a lawyer who will testify at trial from acting as counsel in pretrial discovery
B. holding that where no discovery order was violated sanctions could not imposed pursuant to rule 37 but nevertheless upholding the sanction order under the courts inherent power
C. holding that correspondence between counsel cannot suffice as a rule 34 request that may be compelled through rule 37
D. holding that judge presiding at trial may not testify in that trial as witness
E. holding that lawyers who were necessary witnesses in the case under rule 37 were not prohibited from representing their clients in all pretrial matters including discovery
Reply with [A, B, C, D, E] only.