(a) Form and Admissibility. In all trials the testimony of witnesses shall be taken orally in open court, unless otherwise provided by statute or by these rules. All evidence shall be admitted which is admissible under the statutes of this State, or under the rules of evidence applied in the courts of this State. The competency of a witness to testify shall be determined in like manner. (c) Affirmation in Lieu of Oath. Whenever under these rules an oath is required to be taken, a solemn affirmation may be accepted in lieu thereof. (d) Examination of Witnesses. While examining or cross-examining a witness an attorney shall stand, unless the court otherwise permits. R.I. Dist. R. Crim. P. 26