Evidence Act: Witness Identity Reveal

A is accused of murdering B. A friend, C, who witnessed the crime, testifies in A's favour. Unbeknownst to the court, C was earlier a co-accused in the same case but was acquitted due to lack of evidence. However, during cross-examination, defence's lawyer reveals C's prior co-accused status, which C had never disclosed in her testimony. This creates an issue of bias in C's testimony. A now claims that C's prior involvement in the case renders her testimony unreliable.

What is the legal remedy available to A in this scenario?