Under the principle, the relevant places for filing suit are tied to the defendant, the defendant's residence or place of business, plus wherever the cause of action arose. The plaintiff's own location does not create a valid forum, so UP, where B carries on business, can be set aside immediately since B is the plaintiff here, not the defendant.
That leaves two real candidates. A, the defendant, carries on business in Haryana, which satisfies the business ground directly. The agreement was also signed and was to be performed, delivery included, in New Delhi, which makes New Delhi the place where the cause of action arose, satisfying the second ground.
Since the principle does not force a plaintiff to pick just one of several available grounds, both Haryana and New Delhi remain open to B, and any option that drops one of these two, or substitutes UP for either, does not match the rule as applied to these facts.
So the correct answer is At Haryana or at New Delhi.
Checking what would need to be different for each option to hold shows where three of the four choices fall short.
With two grounds already present and pointing to two cities, and UP never qualifying in the first place, the option naming both live grounds together is the one that matches.
Therefore, the correct answer is At Haryana or at New Delhi.