The Element of Intent to commit Perjury

At trial for a person who has been charged with perjury, the jury must decide on the element of intent. That is, did the person know that his or her statement was false at the time the statement was given?

Answer the following:

a.) The judge will explain to the jury that to answer this question, the jurors must apply an objective standard. What is the question that the jurors must ask themselves on the question of intent?

b.) At trial, who has the burden of proving the falsehood of the testimony?

c.) What level of proof is required for proving that the testimony was false?