Which type of will is written by the testator in their own handwriting?

A holographic will is a type of will that is entirely written, dated, and signed in the handwriting of the testator. The defining feature of a holographic will is that it does not require witnesses for it to be valid in many jurisdictions, as long as the testator's intent is clear through their handwriting. This type of will is particularly useful for individuals who may want to make a quick amendment or create a will in a situation where formalities may be challenging.

In contrast, a joint will is typically executed by two or more individuals who intend to dispose of their joint property and may not be handwritten. An attested will usually requires the presence and signatures of witnesses, which is not a characteristic of a holographic will. An oral will, although valid in some jurisdictions, is not written and relies on verbal declarations made by the decedent. Thus, when it comes to the characteristic of being handwritten by the testator, the correct answer clearly aligns with the definition and requirements of a holographic will.