As $a, b, c, d$ are in H.P. So $b$ is H.M. between $a$ and $c$. Also G.M. between $a$ and $c=\sqrt{a c}$.
Now, G.M.>H.M. so that $\sqrt{a c} \gt b \Rightarrow a c \gt b^2 \ldots(i)$
Again $a, b, c, d$ are in H.P. So $c$ is H.M. between $b$ and $d$.
Therefore $b d \gt c^2 \ldots(ii)$
Multiplying (i) and (ii), we get
$a b c d \gt b^2 c^2$ or $a d \gt b c$ Hence answer (2) is true.
Now A.M. between $a$ and $c=\frac{1}{2}(a+c)$
Now as A.M. > H.M. so here $\Rightarrow$ $a+c \gt 2 b \ldots(iii)$
And $C$ is H.M. between $b$ and $d \Rightarrow b+d \gt 2 c\ldots(iv)$
Adding (iii) and (iv), we get
$(a+c)+(b+d) \gt 2(b+c) \Rightarrow a+d \gt b+c$
Hence answer (1) is true. So both (1) and (2) are correct.