The data set Zone7b.Pollen tracks the pollen count and other environmental data for a geographical region. To make a drillable graph of pollen types, how should your program begin?

	data work.disper7b; set zone7b.pollen; BarDrill=0; if pollentype='GRASS' then bardrill='grass7b.html'; if pollentype='WEED' then bardrill='weed7b.html'; if pollentype='TREE' then bardrill='tree7b.html';
	data work.disper7b; set zone7b.pollen; length BarDrill $ 40; if pollentype='GRASS' then bardrill='grass7b.html'; if pollentype='WEED' then bardrill='weed7b.html'; if pollentype='TREE' then bardrill='tree7b.html';
	data work.disper7b; set zone7b.pollen; length BarDrill $ 40; if pollentype='GRASS' then bardrill='HREF="grass7b.html"'; if pollentype='WEED' then bardrill='HREF="weed7b.html"'; if pollentype='TREE' then bardrill='HREF="tree7b.html"';