Final answer:
Aminoacyl-tRNA synthetase is the protein involved in translation, as it attaches amino acids to their corresponding tRNA molecules, enabling protein synthesis at the ribosome.
Step-by-step explanation:
The protein involved in translation is d. aminoacyl-tRNA synthetase. This enzyme plays a crucial role in protein biosynthesis by attaching the appropriate amino acid to its corresponding tRNA molecule. This process is essential because the tRNA then brings the amino acid to the ribosome, where the amino acids are linked together in the correct sequence to form a protein based on the sequence of codons in the mRNA. Ribosomal RNA (rRNA), while essential for the structure and function of the ribosome, is not a protein. Neither are mRNA, which is the template for translation, nor topoisomerase and RNA polymerase, which are involved in different stages of DNA replication and transcription, respectively.