Question

source
\hague peace conference fails to bring about arms reduction\ — 1907
\german gunboat threatens french holdings in morocco\ — 1911
\german and british naval buildup increases tension\ — 1912
question
which cause of world war i can best be supported using all of these headlines as evidence?
(1) militarism most likely as they are talking about gunboats and naval buildups
(2) alliances no alliances are being spoken of
(3) terrorism false not true at all
(4) ultimatums not shown mostly

Explanation:

The headlines involve military actions (gunboat threats, naval buildup, arms reduction failure), which relate to militarism (the glorification and buildup of military power). Alliances aren't mentioned, terrorism is irrelevant here, and ultimatums aren't the focus. So militarism is supported.

Answer:

(1) militarism