Consider a Reaction Given By
-In the Standard Notation, the Fractional Surface Coverage

Consider a reaction given by $\begin{array} { l } M \underset { k _ { - 1 } } { \stackrel { k _ { 1 } } { \rightleftarrows } } M _ { a ds } ^ { + } + e ^ { - } \\M _ { a d s } ^ { + }\underset { k _ { - 2 } } { \stackrel { k _ { 2 } } { \rightleftarrows } } M _ { sol } ^ { + }\end{array}$ .
-In the standard notation, the fractional surface coverage ( $\theta$ ) of the adsorbed intermediate $$M _ { a t } ^ { + }$$
is described by

A) $$\Gamma \frac { d \theta } { d t } = k _ { 1 } ( 1 - \theta ) - k _ { 2 } \theta$$
B) $$\Gamma \frac { d \theta } { d t } = k _ { 1 } ( 1 - \theta ) - k _ { - 1 } \theta - k _ { 2 } \theta + k _ { - 2 } ( 1 - \theta ) C _ { M _ { 2a d } ^ { 2 + } }$$
C) $$\Gamma \frac { d \theta } { d t } = k _ { 1 } ( 1 - \theta ) - k _ { - 1 } \theta$$
D) $$\Gamma \frac { d \theta } { d t } = k _ { 1 } ( 1 - \theta ) - k _ { - 1 } \theta - k _ { 2 } \theta + k _ { - 2 } C _ { M _ { s a } ^ { 2+ } }$$