Loved them all!

Locked together – hm, sounds plausibly dodgy, so I’ll reject it. Collagen – maybe not. Theatrical term yet I don’t know it: Col + Lux – no, wouldn’t mutate to ~uct, so definitely not the popular choice. Clerical unction – eurgh, I really hope it’s not! Wrestling – can’t think of many terms from this sport – hmm. Sea creatures – too cute, maybe. Mourning together: could be (another Latin col~ word). Jung – hah, good try! (was that you, Sparteye?) Square dance: fancy name, wouldn’t it be?

So I go with (i), out of desperation. Got a feeling this is a red herring though!