At the top of the swing, both gravity and the tension of the string will be in the same direction, thus, this is where tension would be at a minimum. 

At the very limit of being taught, 

Thus,

Solving for 

This will be the linear velocity.

The angular velocity will be 

Combining equations

Plugging in values

Let's go through each answer choice one by one. The force of gravity on the ball is always its mass times gravity, which is constant. The string's pull on the ball is always perpendicular to the ball's motion, so it isn't doing any work, and thus has a constant rate of work . The ball's angular momentum is always constant since its mass, the radius of the circle it's traveling in, and its speed are constant. The only the changing is the tension in the string. This is true because the ball needs the same center pulling force (centripetal force) throughout its path, but this centripetal force is constantly changing direction. For example, at the top of its path, the centripetal force must be down because that's the direction of the center of its circle of motion, but at the bottom, the centripetal force must be up. There are two forces on the ball, gravity and tension. The force of gravity is always down and constant, so the tension needs to change in order to keep the center pulling force the same. For example, when the ball is at the bottom of the circle, the force of gravity is away from the center of the circle, so tension must be higher to keep the center pull constant.

Circumference of a circle:

Distance plane travels during loop (which will be the circumference)

Centripetal acceleration:

Plugging in values:

Circumference of a circle:

Distance plane travels during loop (which will be the circumference)

Centripetal acceleration:

Plugging in values:

Circumference of a circle:

Distance plane travels during loop (which will be the circumference)

One circle is equal to , thus the linear velocity is:

Using

One circle is equal to , thus the linear velocity is

Using

Use Newton's second law:

One circle is equal to , thus the linear velocity is:

The definition of angular momentum:

Plugging in values:

The equation for centripetal acceleration is:

Where  is the centripetal acceleration on an object,  is the velocity of an object, and  is the radius in which the object moves in a circle.

We can see that mass does not play a role in the centripetal acceleration of an object, so no matter what happens to the mass, the centripetal acceleration remains the same.

The equation for centripetal acceleration is:

Where  is the centripetal acceleration on an object,  is the velocity of an object, and  is the radius in which the object moves in a circle.

The radius has an inverse relationship with centripetal acceleration, so when the radius is halved, the centripetal acceleration is doubled.