Answer:c) Mixed
Explanation: Mixed structure is used in the web-site which is considered as the combination of the hierarchical and linear structures.This is most commonly used structure in large websites having complexity. It has the advantage of being flexible and easily understandable.Helen should also use the mixed website structure for describing the recipes of dishes.
Other options are incorrect because linear structure has content in a line ,protected structure is for protection of website and hierarchical structure has the content in branch pattern or hierarchy.Thus, the correct option is option(c).