Contracts can be defective due to?

The correct answer identifies several factors that can render a contract defective, covering a comprehensive range of issues that may affect the validity and enforceability of a contract. Specifically, contracts can be deemed defective due to illegality, meaning any agreement that involves unlawful activities cannot be enforced by law. Additionally, a contract may be defective if there is improper pressure, such as undue influence or duress, which compromises one party's ability to consent freely. Mistakes, whether mutual or unilateral, can also lead to a contract being flawed, as they may impact the agreement's terms or the intentions of the parties involved.

Misrepresentation refers to false statements made that induce one party to enter the contract, which can be grounds for voiding the contract if the misrepresentation is material. Furthermore, non-disclosure indicates situations where a party fails to disclose significant information that would impact the other party's decision to enter into the contract. By covering these various grounds, the answer highlights the complex nature of contracts and how multiple factors can interplay to make a contract defective.

The other options focus too narrowly on specific issues, failing to consider the broader spectrum of factors that can impact the validity of a contract.