Final answer:
Beryllium is a reactive metal with a high melting point that is used in manufacturing rocket nose cones due to its low density and strength.
Step-by-step explanation:
The element that fits the description of a reactive metal with a high melting point and is used in manufacturing rocket nose cones due to its low density and strength is B) Beryllium.
Beryllium is a lightweight metal that has a high melting point and is extremely strong.
These properties make it ideal for use in aerospace applications such as rocket nose cones, where low weight and strength are crucial factors.
Some relevant information to support this answer is that beryllium is a member of the alkaline earth metals group, which includes elements with similar reactivity and properties.
Additionally, beryllium has a low density, making it suitable for use in lightweight structures.