Are Christians who believe in the Trinity considered People of the Book?

In many verses of the Qur'an, Allah speaks positively about the Ahl-al-kitab (i.e., People of the Book). For example, Muslims can eat their food and marry their women under certain conditions. However, according to Quran 5:72-75 , people who believe in the Trinity are disbelievers; this includes mainstream Christians (Catholics, Orthodox, Protestants, etc.). This makes me think that Trinitarian Christians (i.e., those who believe in the Trinity) are not considered Ahl-al-kitab. This motivates my question: *Question*: Are Christians who believe in the Trinity considered People of the Book?