Molecules responsible for reading amino acid language
Clarifying the premise

As mentioned in my comment, the term “amino acid language” doesn’t really make sense as far as I’m concerned. Worse: nothing, to my knowledge, is ever reading an amino acid sequence in living systems.

Yet here we are. The term “amino acid language” itself is definitely used (though, once again, I’ve never heard of anything “reading” this language).

So, to answer the question, let’s define a meaning for the term “amino acid language”:


  The amino acid language is a language written by amino acids. In other words, a set of sequences consisting of amino acids.


The candidates

Now, your question is multiple choice so it’s sufficient to go through all possible choices and see if they fit:


  
  RNA polymerase enzyme
  


RNA polymerase reads either DNA (DNA-dependent RNA polymerase) or RNA (RNA-dependent RNA polymerase) and produces RNA. There are no amino acids involved. This is clearly not the right answer.


  
  mRNA
  


mRNA is an information-carrying molecule. But it does not “read” anything (at least not in its canonical function). Note that other RNAs are involved in recognising/reading things, but not mRNA. So, not the answer.


  
  tRNA
  


tRNAs (transfer RNAs) are RNAs that carry individual amino acids. Each individual tRNA recognises a codon on an mRNA via complementary base pairing and thus “translates” the codon into a specific amino acid by the rules of the genetic code. In the context of this question, it’s fair to say that tRNAs (in combination with other molecules) are writing the amino acid language.


  
  DNA
  


DNA, like mRNA, is an information-carrying molecule that does not read anything. Moving on.

The answer

tRNAs do not read amino acids in the conventional meaning of the phrase. But it’s the closest candidate here: not only does it indeed read a language, it translates symbols into amino acids. This is therefore almost certainly the expected answer, unless an acceptable answer is “none of the above”.