What should be the correct basis for giving extra authority to a partner in the partnership deed?

Correct answer: Consent of all partners

The direct answer is option A: extra authority should be based on the consent of all partners. A partnership is formed and governed by mutual agreement, so giving one partner additional power should be clearly accepted by the partners and preferably recorded in the deed or another written decision. This identifies the scope of authority and prevents later disputes. Option B, only customer demand, cannot alter the partners' internal rights. Option C, a bank advertisement, has no authority to change the partnership agreement. Option D, an employee's wish, is not the consent of the owners and therefore cannot grant a partner legal or managerial power. Thus A is correct. Written consent is especially useful because everyone can later check what authority was actually granted. Memory cue: partnership decisions rest on mutual consent, not outside pressure.