The correct answer is A) The welding must be completed before the riveting commences. When connecting a member by both riveting and welding, the welding should be done first before the riveting process begins. This is because the heat and stress involved in the riveting process can potentially damage or compromise the integrity of the weld if it is done after the welding. Performing the welding first ensures the weld is fully established and able to withstand the stresses of the subsequent riveting operation without being damaged or broken. The other answer choices are incorrect because: B) Tearing through the member is more likely if the welding is done after riveting, not before. C) The weld actually decreases the tensile stress on the rivet heads, not increases it. D) The weld is less likely to be broken by the stresses of riveting if the welding is done first.