Step 1: Write down the standard decay pairs from memory.
The common radiometric clocks used in geology run as follows: $^{238}\text{U} \to {}^{206}\text{Pb}$, $^{235}\text{U} \to {}^{207}\text{Pb}$, $^{232}\text{Th} \to {}^{208}\text{Pb}$, $^{87}\text{Rb} \to {}^{87}\text{Sr}$, $^{147}\text{Sm} \to {}^{143}\text{Nd}$ and $^{40}\text{K} \to {}^{40}\text{Ar}$.
Step 2: Compare each option against this list.
Option (A) says $^{87}\text{Rb} \to {}^{86}\text{Sr}$, but the real daughter of rubidium-87 is strontium-87, not 86. This does not match.
Option (C) says $^{235}\text{U} \to {}^{206}\text{Pb}$, but uranium-235 actually ends at lead-207. This does not match either.
Option (D) says $^{238}\text{U} \to {}^{207}\text{Pb}$, but uranium-238 actually ends at lead-206. The isotopes have been swapped, so this is wrong too.
Step 3: Find the one that matches.
Option (B), $^{147}\text{Sm} \to {}^{143}\text{Nd}$, matches the standard samarium-neodymium pair exactly.
Step 4: Conclude.
\[ \boxed{^{147}Sm \rightarrow\ ^{143}Nd} \]