State the structural formulas for the following compounds: a) 2-octyne b) ethylisopentylacetylene c) ethynylbenzene d) cyclohexylacetylene e) 5-methyl-3-octyne f) trans-3,5-dibromocyclodecyne g) 5,5-dibromo-4-phenylcyclooct-1-yne h) (E)-6-ethyloct-2-en-4-yne i) 1,4-heptadiyne j) vinylacetylene k) (S)-3-methyl-1-penten-4-yne.