def _set_plot_option_defaults(b_plot):
    """Set default plot options."""
    b_plot.outline_line_color = None
    b_plot.grid.grid_line_color = 'navy'
    b_plot.axis.axis_line_color = None
    b_plot.axis.major_tick_line_color = 'navy'
    b_plot.xaxis.visible = False
    b_plot.yaxis.visible = False
    b_plot.xgrid.visible = True
    b_plot.ygrid.visible = False
    b_plot.xgrid.minor_grid_line_color = 'navy'
    b_plot.xgrid.minor_grid_line_alpha = 0.1
    b_plot.xgrid.grid_line_color = 'navy'
    b_plot.xgrid.grid_line_alpha = 0.1
    b_plot.axis.major_label_standoff = 0
