Plotting the required diagram we get,

Now from diagram we can say that,
sinx is maximum for x∈(−π,4−3π)∪(4π,π) and cosx is maximum for x∈(4−3π,2−π)∪(2−π,4π)
So, area of the region is given by,
A=∣∫−π4−3πsinxdx∣+∣∫4ππsinxdx∣+∣∫4−3π2−πcosxdx∣+∣∫2−π4πcosxdx∣
⇒A=∣21−1∣+∣1+21∣+∣−1+21∣+∣21+1∣
⇒A=2+22+2−22=4
Hence this is the required option.