Basidiocarps are developed by:

Explanation

The correct answer is secondary mycelium. This stage occurs after the primary mycelium has established itself and involves the fusion of cells from two different primary mycelia, leading to a dikaryotic state. This dikaryotic secondary mycelium is capable of forming basidiocarps, which are the fruiting bodies of basidiomycete fungi. Primary mycelium is important for initial growth and nutrient absorption but does not lead to fruiting body formation. Tertiary mycelium refers to further structural developments in some fungi, but is not responsible for basidiocarp formation. Quaternary mycelium is not a recognized term in mycology.