how to use the regionprops max(area)?

if true
  clear all;
clc;
img = imread('40.jpg');
tic
I = rgb2hsv(img);

channel1Min = 0.956; channel1Max = 0.006;

channel2Min = 0.594; channel2Max = 0.886;

channel3Min = 0.529; channel3Max = 0.780;

sliderBW = (I(:,:,1) >= channel1Min ) | (I(:,:,1) <= channel1Max) &(I(:,:,2) >= channel2Min ) & (I(:,:,2) <= channel2Max) & (I(:,:,3) >= channel3Min ) & (I(:,:,3) <= channel3Max);

BW = sliderBW;

bw3 = areaimg(BW);

%bw3 = ratioimg(bw3);

imshow(bw3);

S = regionprops(bw3,'BoundingBox','Area');

BW_2 = imcrop(img,[S.BoundingBox(1,:)]);

imshow(BW_2);

end

i want to crop the max(area) image but show the error:

Expected one output from a curly brace or dot indexing expression, but there were 5 results.

Error in numbertestok (line 22) BW_2 = imcrop(img,[S.BoundingBox(1,:)]);

how to use the max area as i want to extract the image