Undisclosed principal can require third party to fulfill the contract, unless
i. undisclosed principal was expressly excluded as a party in the written contract
ii. contract is negotiable instrument signed by agent with no indication of signing in a representative capacity
iii. performance of agent is personal to contract allowing third party to refuse principal's performance
iv. all of the above

iv. All of the above

Explanation:

An undisclosed principal is a principal where the third party is unknown about the principal of the contract. The third party also does not know that at the time of contract, the  agent is acting in the agency.

The undisclosed principal requires third party to fulfill the contract except :

i. Undisclosed principal was expressly excluded as a party in the written contract

ii. Contract is negotiable instrument signed by agent with no indication of signing in a representative capacity

iii. Performance of agent is personal to contract allowing third party to refuse principal's performance

Thus the answer is

iv. All of the above

as university of miami psychologists debra lieberman and adam smith pointed out in a recent article in the journal current directions in psychological science, humans have social and psychological mechanisms to deter incest. with very few exceptions, marriages between brothers and sisters and between parents and their children are verboten in every human culture. the primary psychological anti-incest mechanism is the yuck response. even the idea of sex with their mom or dad, bro or sis is upsetting to most people. the psychologist jonathan haidt has found that nearly everyone is repelled by the prospect of brother-sister sex, even in hypothetical situations in which there is no chance of pregnancy).

the biological cost of incest

this raises an interesting question: just what’s so bad about incest? sure, having sex with your dad or your sister seems gross — but why? some anthropologists have argued that incest taboos are learned social conventions. this explanation, however, doesn’t make sense to me as it does not explain the widespread existence of anti-incest mechanisms in creatures ranging from cockroaches to chimpanzees. second, the incest taboo is about as close to a universal law as human moral rules get.

why should mechanisms to avoid incest be so widespread both in nature and across human societies? the answer is simple. the problem with having sex close with relatives is that there is an astonishingly high chance that your offspring will be born with a serious birth defect.