In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

What is the lowest ISO mentioned?, Context: Some high-speed black-and-white films, such as Ilford Delta 3200 and Kodak T-MAX P3200, are marketed with film speeds in excess of their true ISO speed as determined using the ISO testing method. For example, the Ilford product is actually an ISO 1000 film, according to its data sheet. The manufacturers do not indicate that the 3200 number is an ISO rating on their packaging. Kodak and Fuji also marketed E6 films designed for pushing (hence the "P" prefix), such as Ektachrome P800/1600 and Fujichrome P1600, both with a base speed of ISO 400.
400

What is beneficial to London's economy?, Context: London is one of the leading tourist destinations in the world and in 2015 was ranked as the most visited city in the world with over 65 million visits. It is also the top city in the world by visitor cross-border spending, estimated at US$20.23 billion in 2015 Tourism is one of London's prime industries, employing the equivalent of 350,000 full-time workers in 2003, and the city accounts for 54% of all inbound visitor spend in UK. As of 2016 London is rated as the world top ranked city destination by TripAdvisor users.
Tourism

Why wasn't Luther eager about the plan?, Context: The catechism is one of Luther's most personal works. "Regarding the plan to collect my writings in volumes," he wrote, "I am quite cool and not at all eager about it because, roused by a Saturnian hunger, I would rather see them all devoured. For I acknowledge none of them to be really a book of mine, except perhaps the Bondage of the Will and the Catechism." The Small Catechism has earned a reputation as a model of clear religious teaching. It remains in use today, along with Luther's hymns and his translation of the Bible.

I acknowledge none of them to be really a book of mine