Upon acquittal, a co-accused can be:

Solution (By Examveda Team)

Option A: A witness for the prosecution only
This option suggests that upon acquittal, a co-accused can only testify on behalf of the prosecution. However, this is not accurate. After being acquitted, a co-accused can testify for either the prosecution or the defense, depending on the circumstances of the case. Therefore, this option is incorrect.

Option B: A witness for the defence only
Similarly to option A, this option implies that a co-accused, upon acquittal, can only testify on behalf of the defense. However, this is not correct. A co-accused can be called upon to testify for either the prosecution or the defense, depending on the needs of the trial. Therefore, this option is also incorrect.

Option C: A witness for the prosecution as well for the defence
This option correctly acknowledges that upon acquittal, a co-accused can serve as a witness for both the prosecution and the defense. Depending on the circumstances of the case and the testimony they can provide, a co-accused may be called upon by either side to testify in court. Therefore, this option is correct.

Option D: An informal witness
This option suggests that a co-accused, upon acquittal, becomes an "informal witness." However, the term "informal witness" isn't a recognized legal classification. Witnesses in court proceedings are typically categorized as witnesses for either the prosecution or the defense, or as expert witnesses. Therefore, this option is incorrect.

In summary, option C: "A witness for the prosecution as well for the defence" is the correct choice, as it accurately reflects the possibility for a co-accused to testify for both sides in a legal proceeding following their acquittal.