Drying to Constant Mass Is a Common Gravimetric Analysis Technique

Multiple Choice

Drying to constant mass is a common gravimetric analysis technique.Which of the statements describe the source of false weights?
I A warm crucible
II Touching the crucible with bare fingers
III Using a microwave oven to dry reagents and crucibles
IV Using a desiccator

A) I,II,and III
B) II,III,and IV
C) I and II
D) II and IV
E) III and IV