13. In the ______ portions of the mRNA transcript are cut out and removed. The remaining regions of the mRNA called ______ are ligated back together and translated in the ______.
a. nucleus, introns, nucleus
b. cytoplasm, exons, nucleus
c. nucleus, exons, cytoplasm
d. ribosome, signal recognition particles, rough endoplasmic reticulum
e. cytoplasm, introns, nucleus