A join B to form business as a Developer called ABC. A owns 60% whilst B owns 40%. ABC appoints XYZ Construction which is owned by A to construct houses. Along the way, XYZ Construction got problem with the quality of the houses. B was dissastify and without prior discussion with A, appoint lawyers and Engineers to take legal action on A and ask for compensation, and also instruct XYZ Construction to stop operating the project.
B also using ABC's letter head to write to A for failing to disclos ABC's income tax to the Inland Revenue Department and seek compensation.

What is A's standing and can A take any legal action in return and on what ground ?