What is the answer and why? (Also, please can you explain why others are not suitable for the answer as well)

John and Kate are partners in international digital, a computer and digital product seller and distributer. It sells computers and digital gadgets. Dissolution of this partnership may be caused only by: A) Only by John and Kate expressly agree to dissolve the partnership. B) only by Kate selling her interest in the firm/partnership to Mark without John's consent. C) only by Kate adding Mark as a new partner without John's constant. D) by the partners agreeing to dissolve their firm/partnership, or by one partner, without the others concerned, selling his/her interest to a third party or adding another partner