Final answer:
The excerpt from the business letter in question has a tone that is authoritative and respectful, combining politeness with decision-making clarity.
Step-by-step explanation:
The tone of the excerpt from the business letter can be described as both authoritative and respectful. The phrase 'We are pleased' conveys a sense of appreciation and politeness, which aligns with a respectful tone. Furthermore, the direct approach of offering the position and proposing a start date reflects an authoritative tone, as it displays an element of decision-making and direction. The tone displays professionalism and avoids being overly casual or critical, adhering to the standards of effective business communication.