Which of the following will sum up all the integers between 1 and 10, inclusive?

a.
```
var sum = 0;
for (var i = 1; i < 11; i ++)
sum = sum + i;
```

b.
```
var sum = 1; var i = 1;
while(i < 11)
sum = sum + i;
```

c.
```
var sum = 1; var i = 1;
while(i != 10)
{
i++;
sum = sum + i;
}
```

d.
```
var sum = 0;
for (var i = 1; i < 10; i++)
sum = sum + i;
```

a.
```
var sum = 0;
for (var i = 1; i < 11; i ++)
sum = sum + i;
```