PROMPT ANALYSIS

a and b are real numbers with a greater than b

SUPER SET

The difference between b and a can be from zero to infinity

TRANSLATION

Since a and b are two variables, we need

The exact value of a and b

Two equation with only a and b s variable

Some characteristics of a and b that may narrow down the possible solution to only one.

STATEMENT ANALYSIS

St 1: a = 4b. Since b can take infinite possible values.NOT SUFFICIENT. Hence option a and d eliminated.

St 2: a+b = 100. A and b again can take infinite possible values. NOT SUFFICIENT. Hence option a, b and d is eliminated.

St1 & St 2: we have two equations and two variable. By solving, we get a =80, b = 20. Therefore, a - b = 60. SUFFICIENT. Option E eliminated.

Hence Option C is the answer.

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