Verified Answer :

SoapyMcTavish

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.

Hope this Helps :)

Answer:

1) Methyl orange

Explanation:

Acid base indicators are solutions of certain dyes that bring about a color change at a certain pH i.e. the at a particular H+ ion concentration.

The color change and the pH range for the four indicators mentioned in the question are as follows:

 indicator                            pH range             color change

1. Methyl orange                  3.2-4.4                 red-yellow

2. Bromothymol blue           6.0-7.6                yellow-blue

3. Bromocresol green          3.8-5.4                yellow-green

4. Thymol blue                      8.0-9.6               yellow-blue

Based on the above data, only methyl orange is yellow at pH above 4.4. Hence,  indicator is yellow in a solution with a pH of 9.8 is methyl orange