The correct answer is option 3 - tightly packed mycelium.

Option 1 - A mass of fungal spores is not the common edible mushroom. Fungal spores are reproductive structures that are produced by mushrooms, but they are not the mushroom itself.

Option 2 - A type of hypha is also not the common edible mushroom. Hyphae are thread-like structures that make up the body of a fungus, including mushrooms. However, a single hypha or a type of hypha is not equivalent to the whole mushroom.

Option 4 - A structure used for producing asexual spores is not the common edible mushroom either. While mushrooms do produce spores, they can reproduce both sexually and asexually. The mushroom itself is the reproductive structure that produces spores, but it is not solely used for producing asexual spores.

Therefore, the correct answer is option 3 - tightly packed mycelium. Mycelium refers to the network of hyphae that form the body of a fungus, including the common edible mushroom. It is the main part of the fungus that is typically found underground or within the substrate that the mushroom grows on.