Question

Which statement about arable land in Pakistan is not true? Farmers irrigate land to make it arable in Pakistan. The Tarbela Dam has helped turn millions of acres into arable land. Arable land is found in most parts of Pakistan. The Indus River is an important source of water for arable land.

Answer 1

The false statement (as noted also by HistoryGuy):
"Arable land is found in most parts of Pakistan."

That statement is quite false. The Library of Congress Country Studies/Area Handbook Series noted that about 60% of Pakistan's land is generally classified as unusable for forestry or agriculture because it is desert, mountain slope, or an urbanized area. The same country study reported that the minimal amount of rainfall that most of the country receives means that about 80 percent of agriculture in Pakistan is dependent on irrigation. The other three answers in your question (all about damming and irrigation) are true items.

Answer 2

"Arable land is found in most parts of Pakistan" is not true, since most of this land has to be artificially created through specific irrigation techniques that make it plantable.