In a certain code language 'is op er' means 'book is thick', 'it an er' means 'bag is heavy', 'ak is' means 'interesting book' and 'ed it' means 'that bag'. Which of the following means 'that is interesting' in that code language?
it op ak
ed is er
ak er an
ak ed er
'op' stands for thick, 'an for heavy', 'ak for interesting' and 'ed' for that'.