display = block in the bootstrap code example
Example 1: bootstrap display inline block
<div class="d-inline-block"></div>
Example 2: bootstrap display block
<div class="d-block"></div>
d-block = for displaying
d-none = to hide
<div class="d-inline-block"></div>
<div class="d-block"></div>
d-block = for displaying
d-none = to hide