Given
$L_1=\{a^nb^nc^n | n\geq 0\}$
$L_2 =\{a^nb^mc^k|k=n+m \text{ and }n,m\geq 0 \}$
$L_3 =\{a^nb^mc^k|n,m,k \geq 0 \}$
Assume
$L_4=L_1 (L_3)^*$
$L_5=(L_1\cap L_2)\cup L_3 $
Which of the following statement is correct?
A. L4 is regular and L5 is not regular
B. L4 is CFL and L5 is not CFL
C. Both L4, L5 are regular
D. Both L4, L5 are CFL but not regular