Evaluate the Improper Integral $\int _ { 0 } ^ { \infty } x ^ { 3 } e ^ { - x ^ { 4 } n } d x$

Multiple Choice

Evaluate the improper integral: $\int _ { 0 } ^ { \infty } x ^ { 3 } e ^ { - x ^ { 4 } n } d x$ Round to two decimal places,if necessary.

A) 1.75
B) Undefined
C) 3.5
D) 2.63