As a possible answer for my own question, I found the following from https://www.journalofaccountancy.com/issues/2004/sep/employerprovidededucationbenefits.html
"According to Treasury regulations section 1.117-4(c), if an employer pays for an employee’s study or research, and those amounts represent payments for past, present or future employment services, the employee must include them in his or her income. Amounts that enable an employee to pursue studies or research primarily for the employer’s benefit also are deemed taxable income. Using the terms “scholarship” or “fellowship grant” and funding education without some consideration of these rules may lead to undesired tax consequences. Indeed, the IRS found its own scholarship program to be a taxable benefit in revenue ruling 76-230 because its student-trainees were receiving the education in exchange for future services."
So it seems B and D are foreign earned income and C is tax-free health coverage. Not sure about A.
