The correct answer is letter b.
The excerpt is written in the Simple Past and narrates a series of events that happened in a sequence.
Notice the verbs in the Simple Past : wept, wailed, fell, faded and died.
There is a verb missing in the part " the earth stiff and cold" The verb is grow, the Simple Past form is grew, therefore " the earth grew stiff and cold" is the correct way.
Letter A is wrong because there's a verb missing.
Letter C and letter D " the earth was growing stiff and cold" the verb grow is in the Past Continuos, " the leaves were falling from the sorrowing trees" the verb fall is also in the Past Continous breaking the pattern stablished.
