An inexperienced speaker should
(A) Take a copy of his/her entire speech to the platform.
(B) put brief notes giving the main points of the speech on 3'' by 5'' cards and take these to the platform.
(C) memorize his/her entire speech and use no notes.
In many senses, this is a false trichotomy. There are many different methods that inexperienced speakers can use to speak comfortably and naturally in public. Which method a speaker should choose depends entirely on the speaker's own individual talents and abilities. Each one of these choices has its own strengths and potential pitfalls.
A) Reading a speech aloud from a written text: There are several advantages to this method. The main one is that you can compose the speech carefully, choosing each word for maximum effect, rather than rambling at random. Also, if you are prone to stage fright, you can just read from a script and won't lose track of what you intend to say. Good speakers who use this method rehearse extensively, planning and marking how they will say every phrase, and even marking where they will breathe. There are several disadvantages to this method for inexperienced speakers, though. First, composing spoken discourse requires use of different vocabulary and syntax than is normally used in writing. Second, and even more important, reading aloud naturally from a script is a skill that normally takes a fair amount of practice. The key technique is reading at least one sentence ahead of what you are saying. Many inexperienced speakers cannot do this naturally and will sound wooden and awkward and be unable to maintain eye contact with the audience.
B) Using brief notes: This has the advantage of ensuring that you have your main points and general structure written, but avoids the performance issues of verbatim reading. The downside is that very few people can improvise eloquently, shaping sentences that are concise, grammatical and persuasive. While it leads to more natural performance than verbatim reading, it may lead to lower quality speeches.
C) Memorizing speeches: The great performances of the theater are based on memorization. A skilled speaker memorizes not just words but tones and inflections and gestures, creating a polished performance that appears natural and convincing, but in which every word, gesture, and pause has been perfectly crafted. Although this will result in the best possible speech, it takes the most work. Professional stage actors will normally rehearse several hours a day for a month or more to perfect memorized performances of their roles. An inexperienced speaker can give a good performance this way, but the result can seem stilted and unnatural if it is not done well.