Crossing a true$-$breeding red flowered and a true$-$breeding blue flowered petunia results in offspring that have red and blue speckled flowers. What phenotypic ratio do you expect from crossing a plant with red and blue speckled flowers with a blue flowered plant?

$3$ blue : $1$ speckled

$1$ blue : $1$ speckled

$1$ red : $2$ speckled : $1$ blue

All the offspring will be speckled