The Local Truncation Error for the Improved Euler's Method Is $O ( h )$

Multiple Choice

The local truncation error for the improved Euler's method is

A) unknown
B) $O ( h )$
C) $O \left( h ^ { 2 } \right)$
D) $O \left( h ^ { 3 } \right)$
E) $O \left( h ^ { 4 } \right)$