In order to see if the comparisons are true we need to see what each fraction is equal to
a.

According to this the statement is false, because 0.86 is greater than 0.75
b.

For the second one we can start by simplifying the fractions

The expression is false because because when talking about fractions as bigger the number gets on the denominator, smaller the equivalent to the fraction gets.
Meaning that 1/3 is bigger than 1/4.
c.

start by simplifying the fraction that can be simplified

find the equivalent to the fractions


The comparison is true because 0.4 is greater than 0.17
d.

start by simplifying the fractions

rewrite the expression

Since both fractions have the same denominator, and 2 is greater the 1 the expression is false.