Which of the following can be a reason for a will to be declared invalid?

A will may be declared invalid for several significant reasons, which are all encompassed in the chosen answer. Witnesses are crucial for validating a will, as many jurisdictions require the presence of witnesses during the signing process to confirm that the testator is following legal protocols and is doing so voluntarily. If witnesses are absent when the will is executed, this absence can lead to the will being contested and possibly deemed invalid.

Additionally, a holographic will, which is often a handwritten document that may not have the formal witness requirements, still needs to be properly executed according to state law. If a holographic signature is insufficient or the document does not meet the legal standards required for a will, it can also be declared invalid.

Moreover, the testator's capacity is a fundamental aspect of a valid will. If the individual creating the will lacks the mental capacity to understand the nature and implications of their actions—such as being under duress or suffering from a mental impairment at the time of signing—the will may be declared invalid.

Given that all of these factors can independently lead to the invalidation of a will, the comprehensive reasoning justifies selecting the option that includes all of these possibilities as valid reasons for a will's invalidity.