Which is the most effective placement of an item in a design to control emphasis?

Center

Explanation:

    Emphasis is the Design Principle also known as Visual Focus or Focal Point. It aims to direct the gaze to some specific object, element or composition.

    Using the Contrast principle, for example, achieves this goal, but the Emphasis can be applied by other means, such as the isolation of an object (which draws more attention than the objects that are grouped together), or by an unusual position. some compositional element in the environment and even by the proper lighting.

   By directing the gaze, this principle can be used to disguise unwanted irregularities. But be careful of overemphasis as it can cause the feeling of confusion, conflict and visual discomfort.