How to remove spacing in b-form-radio-group and let the radio fill the column space?

I created a b-form-radio-group of radio buttons, but the default class of b-form-radio is form-check-inline, which leads to the spacing betweeen radios. How to change the default class so that I can remove the space and make the radios fill the column space?

          <div style="display: inline; justify-content: space-around">
            <b-form-group>
              <b-form-radio-group
                id="radio-slots"
                v-model="formulaSign"
                :options="formulaSignOptions"
                buttons
                button-variant="outline-dark"
                :disabled="!editMode"
              >
              </b-form-radio-group>
            </b-form-group>
          </div>

The result is as below:

output