Which of the following types in Terraform is considered a complex type?

In Terraform, complex types include structures that can contain multiple values of different types, allowing for more sophisticated data representation. A structural type is one of these complex types, often referred to as an object or a map, which can encapsulate varied data types and nested structures into a cohesive unit.

Structural types are particularly useful when defining configurations that require grouping related information, such as defining resource attributes that may vary in type or structure. For example, a structural type can represent a resource with various properties, where each property could be of a different basic type, like strings, numbers, or even other complex types.

In contrast, the other types listed are considered simple types. A number and a float64 type both represent numeric values, while a string is simply a sequence of characters. These types lack the capability to compose diverse data elements into a single unit, which is why they are not classified as complex. Understanding the distinction between simple and complex types is essential for effectively managing data structures in Terraform.