Imo the text is trivially clear on this point. Military Academy is a pre-career option.
A Traveller attends the pre-career option of Military Academy (Marines) and receives the Marine Service Skills: Athletics-0, Vacc Suit-0, Tractis-0, Heavy Weapons-0, Gun Combat-0, and Stealth-0 "as with basic training". He graduates (increasing three of these skills to Level-1 and gaining EDU+1) and is granted automatic entry to the Marines.
When he begins his first term of the Marine career:
A) Because the Military Academy was a pre-career option and not a career, "Marine" counts as his first career. As per the "Basic Training" rule on page 18, during his first term instead of rolling for a skill he undergoes Basic Training and receives the skills on the Marine Service Skills table: Athletics-0, Vacc Suit-0, Tractis-0, Heavy Weapons-0, Gun Combat-0, and Stealth-0. Since he already has all of the Service Skills at level 0 or higher this provides no benefit.
B) Because the Military Academy provided Basic Training, the Marines count as his second instance of receiving Basic Training in a career, so as per the "Basic Training" rule on page 18, for his first term of service instead of rolling for a skill he selects one skill from the Service Table and receives it at Level-0. Since he already has all of the Service Skills at level 0 or higher this provides no benefit.
C) Because the Military Academy already provided the Marine Basic Training he receives a skill roll on any of the Marine skill tables he qualifies for during his first term instead of Basic Training, even though this is his first term in his first career.
Which is the correct RAW?