Answer: D. [tex]\dfrac5{12}[/tex]
Step-by-step explanation:
Fraction of granola bar Owen ate = [tex]\dfrac13[/tex]
Fraction of bar Bella ate = [tex]\dfrac14[/tex]
Whole bar is considered as 1.
Part of bar left uneaten = [tex]1-\dfrac13-\dfrac14=\dfrac{12-4-3}{12}[/tex]
[tex]=\dfrac{5}{12}[/tex]
Owen and Bella left [tex]\dfrac5{12}[/tex] of the bar uneaten.
Hence, the correct option is D. [tex]\dfrac5{12}[/tex]