Which of the following represents the plot of height v/s refractive index of elevated surface duct?

• A. <img alt="The plot of height v/s refractive index of elevated surface duct - option a" class="alignnone size-full wp-image-276354" height="140" src="https://www.sanfoundry.com/wp-content/uploads/2020/05/antennas-questions-answers-space-wave-propagation-duct-propagation-q6a.png" width="135"/>
• B. <img alt="The plot of height v/s refractive index of elevated surface duct - option b" class="alignnone size-full wp-image-276355" height="109" src="https://www.sanfoundry.com/wp-content/uploads/2020/05/antennas-questions-answers-space-wave-propagation-duct-propagation-q6b.png" width="153"/>
• C. <img alt="The plot of height v/s refractive index of elevated surface duct - option c" class="alignnone size-full wp-image-276356" height="140" src="https://www.sanfoundry.com/wp-content/uploads/2020/05/antennas-questions-answers-space-wave-propagation-duct-propagation-q6c.png" width="138"/>
• D. <img alt="The plot of height v/s refractive index of elevated surface duct - option d" class="alignnone size-full wp-image-276357" height="131" src="https://www.sanfoundry.com/wp-content/uploads/2020/05/antennas-questions-answers-space-wave-propagation-duct-propagation-q6d.png" width="142"/>