Question

hypothesis: if a mouse inherits a particular form of one trait, then the inheritance of the other trait will not be affected because alleles assort independently.
the hypothesis would not have been supported by the data if
traits independently assorted in approximately a 9:3:3:1 ratio.
the traits for white fur and red eyes were always inherited together.
all the f1 offspring had the same phenotype

Explanation:

The hypothesis is about independent assortment of traits (Mendel's law). If traits are always inherited together, that means they are linked (violating independent assortment), so the hypothesis (that inheritance of one trait doesn't affect another) would not be supported. The 9:3:3:1 ratio supports independent assortment, F1 same phenotype is typical of dominant/recessive, but linked traits (always inherited together) contradict independent assortment.

Answer:

the traits for white fur and red eyes were always inherited together.