Why did technology make it difficult for armies on the western front to mount successful offensive attack ?

Because enemies were able to detect and suppress the weapons.

Explanation:  

Because the technology did allow improved and new weapons that allowed a new way of fighting.

For example, Germany had enemies that detect their weapons. They found how to suppress those weapons(it was the zeppelins filled with hydrogen) and avoid them.

i am sure the answer is d

the president signs or vetoes the bill.