Which Rule Is Used in the Following Inference $G$ $\underline{\mathrm{H}}$ $\mathrm{G} \cdot \mathrm{H}$

Multiple Choice

Which rule is used in the following inference? $G$
$\underline{\mathrm{H}}$
$\mathrm{G} \cdot \mathrm{H}$

A) Simp
B) Conj
C) Add
D) DS
E) HS