The Partnership Act establishes that each partner functions as a principal for their individual interests and as an agent when acting for other partners. The Act further clarifies that the business may be managed by all partners jointly or by a single partner representing the entire group. This aligns directly with Assertion (A), as each partner holds a dual capacity within the partnership. Consequently, both Assertion (A) and Reason (R) are valid, with Reason (R) providing a suitable explanation for Assertion (A).