Which method is suitable for preventing paint from spreading under a stencil?

Correct answer: Use little paint with light vertical pressure

The governing concept of stencil printing is preventing paint from being forced beneath the stencil edge. A small amount of relatively controlled paint, applied with light vertical dabbing or pressure, deposits colour without pushing it sideways. Option B therefore gives the correct method. Watery paint, a loose stencil, or moving the brush under the edge creates paths for bleeding and produces blurred outlines. Keeping the stencil stable is also important.