A. Brush size
B. Color intensity
C. Edge hardness
D. Stroke length

Solution

B. Color intensity

Explanation

<p data-start="68" data-end="172" class="PDq2pG_selectionAnchorContainer">In <strong data-start="71" data-end="90">Adobe Photoshop</strong>, <strong data-start="92" data-end="109">Brush Opacity</strong> controls the <strong data-start="123" data-end="151">transparency (intensity)</strong> of the brush stroke.<span aria-hidden="true" class="PDq2pG_selectionAnchor"></span></p><p> </p><ul data-start="174" data-end="287"> <li data-section-id="ewvszn" data-start="174" data-end="221"> <strong data-start="176" data-end="192">100% Opacity</strong> → Fully opaque (solid color) </li> <li data-section-id="p02p8a" data-start="222" data-end="258"> <strong data-start="224" data-end="239">50% Opacity</strong> → Semi-transparent </li> <li data-section-id="p39clb" data-start="259" data-end="287"> <strong data-start="261" data-end="275">0% Opacity</strong> → Invisible</li></ul>