3. Visitors buy boomerangs and T-shirts with kangaroos.
Solution:
Text 1: "People buy tea and mugs with the Union Jack." matches heading b) British souvenirs. (The Union Jack is a symbol of Great Britain).
Text 2: "Tourists bring matryoshkas and samovars." matches heading a) Russian souvenirs. (Matryoshkas and samovars are traditional Russian items).
Text 3: "Visitors buy boomerangs and T-shirts with kangaroos." matches heading c) Australian souvenirs. (Boomerangs and kangaroos are strongly associated with Australia).