In the broadest sense, the debate over fare increases on New York City subways and buses was over before it began.

Beginning next March, transit officials have said, the fares will be going up. The Metropolitan Transportation Authority’s budget depends on it.

But the more vexing discussion — of who, exactly, will be asked to pay more — begins in earnest on Monday, when the authority will present four proposals that would raise the required money.

Although the details are subject to change, and the authority may combine components of different proposals before arriving at a final decision, the choices are likely to resemble the following, according to transportation officials with knowledge of the proposals:

¶ The base fare remains at $2.25, but the cost of a 30-day MetroCard rises as high as $125, a $21 increase. A weekly card costs $34, up from $29. In addition, the 7 percent bonus on pay-per-ride MetroCards — which gives a rider an extra $1.40, for example, with each $20 placed on the card — is reduced to 5 percent.