Which indicator is yellow in a solution with a ph of 9.8?
(1) methyl orange (3) bromcresol green
(2) bromthymol blue (4) thymol blue

It's the Methyl Orange. 
at about 4.4 pH, it changes from red to Yellow, to indicate an acid solution.
This pH indicator is normally used in titration of acids.

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What is the question

They are like other investigations? say there was a murder u have to do blood test and finger prints which run through a lab.