The question describes a principal who gives instructions based on their formal position as a representative of the Head of the Education Department. This indicates a leadership style where decisions

The question describes a principal who gives instructions based on their formal position as a representative of the Head of the Education Department. This indicates a leadership style where decisions and directives flow from the top, relying on the leader's authority rather than seeking input or collaboration.

Let's evaluate the options:

1. Autocratic style: This leadership style is characterized by a leader who makes decisions independently and dictates instructions, expecting subordinates to follow without question. The leader's authority is the primary basis for their directives. This aligns well with the description.
2. Situational style: This style involves adapting leadership approaches based on the specific circumstances and the readiness of the followers. It's not solely based on the leader's position.
3. Laissez-faire style: This style is hands-off, giving employees a high degree of autonomy and minimal direct instruction. This is the opposite of the described scenario.
4. Authoritative style: While authoritative leaders set clear expectations and direct others, they often do so by inspiring and explaining the vision, rather than solely by virtue of their position in a rigid, command-and-control manner. The emphasis on "by virtue of his position" leans more towards a strict, top-down approach.
5. Democratic style: This style involves leaders consulting with their team members and making decisions collaboratively. This contradicts the idea of giving instructions solely based on position.

The most fitting description for a leader who gives instructions purely by virtue of their formal position is the autocratic style.

The final answer is $\text{1. autocratic style}$