How would P&P theory rule out this sentence

[mallu]

See the sentence
1. *Who1 did he1 say that Mary saw t1.(from Peter W.Cullicover 1997,Principles and Parameters,O.U.P). The author gives an explanation for its ungrammaticality  on the basis of Principle C. I have a vague memory of a principle called 'bijection principle' which would also rule out this sentence,am I correct . Please help

[Daniel]

Are you familiar with the binding theory? Read principles A, B and C. Post back if you have questions.