Select the option that represents the letters that, when sequentially placed from left to right in the blanks, will complete the letter series. R _ S _ _ _ S G R T _ G _ T S _ |
G T R T S G R R G T R S R G T G R S T R G T G R T S R G |
T G R T S R G |
R T S G / R T S G / R T S G / R T S G T G R T S R G |