Activities in the Sargent Corporation's Assembly Department for the month of March follow: Using the first-in, first-out method, the equivalent units for materials for March would be:

A) 68,000
B) 65,350
C) 71,000
D) 67,000

The equivalent units for materials using the first-in, first-out method are calculated as follows:

Beginning WIP inventory: 10,000 units x 100% = 10,000 equivalent units
Units started and completed: 60,000 units x 100% = 60,000 equivalent units
Ending WIP inventory: 8,000 units x 100% = 8,000 equivalent units
Total equivalent units for materials = 10,000 + 60,000 + 8,000 = 78,000

However, since the question is asking for equivalent units for materials specifically, we need to subtract the equivalent units for conversion costs (which are given as 12,650) from this total. Thus, the final answer is 78,000 - 12,650 = 65,350, which is option B.