B

In a suspended type moving coil galvanometer, quartz suspension is preferred because it minimizes elastic after-effects.
Step 1: Understand that in measurements with a galvanometer, precision is key. Elastic after-effects in a material can cause the coil to continue to move or oscillate even after the current is stopped, leading to inaccurate readings.
Step 2: Quartz, as a material, exhibits very low elastic after-effects compared to metals or other materials, making it ideal for this application.
Step 3: Therefore, the correct reason for using quartz in the suspension is that elastic after effects are negligible, providing more accurate and reliable measurements.
Thus, the correct answer is B.