What Is the Rationale Behind the Principle That a Witness

What is the rationale behind the principle that a witness does not have to sign or witness the testator sign a holographic will?

A) When the entire will is in the testator's handwriting, it lessens the chance of fraud or forgery.
B) It is unnecessary and inconvenient to involve other parties if the will is created by the testator.
C) The testator had ample time to consider the consequences of creating the will.
D) The writing is better evidence of the testator's state of mind.
E) Witnesses are required to sign and witness the testator signing a holographic will.