In the Previous Three Problems, the Product Solutions Are
A) $u = J _ { 0 } ( n \pi r / 3 ) \cos ( n \pi z / 3 )$

In the previous three problems, the product solutions are

A) $u = J _ { 0 } ( n \pi r / 3 ) \cos ( n \pi z / 3 )$
B) $u = J _ { 0 } \left( n ^ { 2 } \pi ^ { 2 } r / 9 \right) \cos ( n \pi z / 3 )$
C) $u = J _ { 0 } \left( n ^ { 2 } \pi ^ { 2 } r / 9 \right) \sin ( n \pi z / 3 )$
D) $u = J _ { 0 } \left( z _ { n } r \right) \cosh \left( z _ { n } ( z - 3 ) \right)$
E) $u = J _ { 0 } \left( z _ { n } r / 2 \right) \sinh \left( z _ { n } ( z - 3 ) / 2 \right)$