Explanation:

Fourth option is correct.

The World Day to Combat Desertification and Drought (WDCD) is observed every year to promote public awareness of international efforts to combat desertification. The day is a unique moment to remind everyone that land degradation neutrality is achievable through problem-solving, strong community involvement and co-operation at all levels. The 2018 WDCD urges you to move away from unsustainable land use and make a difference by investing in the future of land under the theme “Land has true value — invest in it”.