Final answer:
Worn valve stem seals can cause both rapid valve stem and guide wear as well as excessive oil consumption.
Step-by-step explanation:
Tech A says that worn valve stem seals may cause rapid valve stem and guide wear. This is because worn valve stem seals can allow oil to leak into the combustion chamber, resulting in oil burning and subsequent valve stem and guide wear. Tech B says that worn valve stem seals may cause excessive oil consumption. This is because when the seals are worn, oil can leak past them and be burned in the combustion chamber, leading to increased oil consumption. Therefore, both Tech A and Tech B are correct in their statements.