Answer & explanation
Correct answer: option 1
for every $L_1∈L$
$L_1⊥L_1$ (Not possible) (Not reflexive)
$(L_1,L_2)∈R⇒L_1⊥L_2⇒(L_2,L_1)∈R$ (Symmetric)
$(L_1,L_2)∈R,(L_2,L_3)∈R$
$L_1⊥L_2$ and $L_2⊥L_3⇒L_1||L_3$ (Not transitive)
Correct answer: option 1
for every $L_1∈L$
$L_1⊥L_1$ (Not possible) (Not reflexive)
$(L_1,L_2)∈R⇒L_1⊥L_2⇒(L_2,L_1)∈R$ (Symmetric)
$(L_1,L_2)∈R,(L_2,L_3)∈R$
$L_1⊥L_2$ and $L_2⊥L_3⇒L_1||L_3$ (Not transitive)